Science Mysteries: How Many Species Are There? You might think that after 200 years, the scientists who find, name, and describe Earth's species would be close to finished. But taxonomists, as organized as they may be, have no idea how many species Earth has. Nor can they even provide an educated guess. Although reporting over 16,000 new species every year, taxonomists still cannot predict how many more are undiscovered. In total, taxonomists have categorized and listed 1.2 million species on Earth. At this point, you would think scientists should be able to use the information they have gathered to make good predictions about how many species an ecosystem can support. This would help them make better predictions about how many species are left to identify. So far, however, the guesses seem to vary so greatly that it seems there is no good theory for making a prediction. One of the main problems is that most of the places that seem to have a lot of diverse species are in places that are hard to get to. One such place is the ocean, where scientists believe some 80 percent of Earth's creatures are hiding at depths too deep for us to study. In addition, many of the planet's most diverse areas are in remote places with few taxonomists. Despite all the unknowns, scientists have agreed that there are between five and 15 million species left to discover on Earth. This is a huge range, but whether it's five or 15, taxonomists clearly still have a lot of work to do. And who knows, there may yet be a dragon or a Loch Ness monster left to discover. Which of the following best paraphrases the paragraph in bold? One problem is that lots of places that may have lots of diverse species are hard to get to. Take the ocean, where taxonomists believe 80 percent of species are hiding. Also, the planet has diverse areas with remote places. Scientists have difficulty finding and identifying over three-quarters of the world's species due to their habitats being out of human reach. Due to deep oceans and isolated locations, many

Answers

Answer 1

Answer: 5 million to 100 million species on the planet, but science has only identified about 2 million. “We’ve only touched the surface of understanding animal life

Explanation:


Related Questions

I heard you asking questions of each: who killed the pork chops? what price bananas? are you my angel? why does the author most likely use free verse for this excerpt? the structure imitates casual conversation. the structure reflects narrative storytelling. the structure mirrors classic poetic principles. the structure suggests an epic tale of morality.

Answers

The author most likely use free verse for this excerpt because the structure imitates casual conversation, as stated in option A and further explained below.

What is free verse?

We say a poem is written in free verse when it has no regular rhythm, and the lines do not rhyme. The poem we are analyzing here is called "A Supermarket in California," by Allen Ginsberg, and the author chooses to use free verse in the excerpt.

The reason for that is the fact that free verse sounds like a casual conversation. As the author lists the questions his imaginary friend - who is Walt Whitman, by the way - asks him, he wants them to sound as normal, casual dialogue.

With the information above in mind, we can choose option A as the correct answer.

Learn more about free verse here:

https://brainly.com/question/1509140

#SPJ1

Answer: it’s a i took the exam

Explanation:

Infer how the narrator feels about the president’s visit (lines 269-286). Use specific textual examples of descriptive language to support your answer.

Answers

It can be inferred from the excerpt that the narrator feels relieved that the President was no longer defensive but touched by the suffering of the people who had undergone the unfortunate incident which is also inferred. See the textual evidence below.

What is the textual evidence for the above?

The textual evidence that supports the above inference is given in Lines  290-291 - "I knew somehow that during the night his defenses had crumbled and he had given in to grief; finally he was vulnerable."

Notice the word "finally". This suggests that the narrator had been waiting for that to happen, hence the inference.

Learn more about textual evidence at;
https://brainly.com/question/375033
#SPJ1

Why is Sierra so upset that the thought "not enough" came from somewhere within herself? How would consistently hearing "not enough" affect some one

Answers

Consistently hearing that one is not enough would affect the self-esteem and worth of the person.

What is Self-Esteem?

This refers to the belief that a person has about himself/herself that he is able to do something and is confident about it.

When a person is constantly talked down on, this can affect the psyche and also the self-esteem.

Hence, we can see that your question is incomplete because you did not specify the name of the book you were referring to, but the second question was answered.

Read more about self esteem here:

https://brainly.com/question/8992294

#SPJ1

What conflict dose Nate face at the beginning of the story? What event in the plot cause Nate to change and grow? Write an essay describing the conflict and how it is resolved. Explain how Nate changes as a result of events

Answers

The conflict that Nate face at the beginning of the story is that he can't join his brother.

What is conflict?

It should be noted that conflict simply means the disagreement that occurs between the authors in a literary work.

His brother was partbof the regiment but he didn't have any work as a man.

Learn more about conflicts on:

brainly.com/question/24769299

#SPJ1

Language that appeals to the senses be included in which type of paragraph?

Answers

Language that appeals to the senses be included in descriptive type of paragraph. In descriptive paragraph, one qualifies. Hence, the need to use language that helps to imagine.

Why do you need to use language that appeals to senses in descriptive paragraph?

Descriptive paragraphs have to centre on vivid and objective description of something to the reader. In order to provide this clear detail, the writer must use language that appeals to the reader's five senses: sight, smell, sound, taste, and touch.

Therefore, the correct answer is given above.

learn more about descriptive essay: https://brainly.com/question/988168

#SPJ1

How to give Directions?

Answers

In order to give directions effectively, one must be able to know the end result that needs to be achieved.

What other skills are required for giving directions?

If you want to give directions to a place or location, you must have a strong pictorial image of the destination you are describing.

It also helps to relate certain  popular terminal points with where the receive of the instructions know already.

Learn more about giving directions at:
https://brainly.com/question/10596677
#SPJ1

What is the purpose of the first paragraph of this section of the Iroquois Constitution?
to describe the meaning of the shell strings
to describe the consequences of disobeying one’s tribe
to describe the traditions of the Lords
to describe the history of each tribe in the Five Nations

Answers

Answer:

The purpose of the first paragraph of this section of the Iroquois Constitution was to describe the meaning of the shell strings.

Hope this helps, L.E.

Answer: answer is A

Explanation:

better to be wrong with everyone then right by yourself. Dance alone and you can jump as much as you wanr meanings

Answers

Answer:

Explanation:

The first sentence means that it is better to be part of a group and not alone even if the group is wrong in what it thinks. Personally I don't think it is a true statement, but what I've written is what it says.

The second sentence has much the same meaning. If you dance alone, you need not worry about what everyone thinks of your dancing or your behavior.

A second level of detail of content should be​ ________.A. near the top of the pageB. lower on the pageC. in a different font than the primary contentD. underlined and italicized

Answers

A second level of detail of content should be in a different font than the primary content.

The term "level of detail" in writing, which is also referred to as "level of abstraction," refers to three ideas: the accuracy with which the appropriate words are chosen to form phrases, clauses, and sentences; the generality of assertions; and the organizational strategy with which writers group concepts into a ranking of detail based on a standard theme.

Since, the level of detail of content is second, it must be written in different font than the primary content so that the reader can identify and differentiate the content on the basis of level of its importance.

Hence, the correct option is C.

To learn more about second level of detail here

https://brainly.com/question/14450770

#SPJ4

Read the sentence.

need the answer qwick

The peripheral nervous system—which is a network of nerves extending from your brain and spinal cord to all parts of your body carries signals back and forth.


Which revision of the sentence is now properly punctuated?


The peripheral nervous system—which is a network of nerves extending from your brain and spinal cord to all parts of your body carries signals back and forth.

The peripheral nervous system (which is a network of nerves) extending from your brain and spinal cord to all parts of your body carries signals back and forth.

The peripheral nervous system which is a network of nerves extending from your brain and spinal cord to all parts of your body carries signals back and forth.

The peripheral nervous system—which is a network of nerves extending from your brain and spinal cord to all parts of your body—carries signals back and forth.

Read the excerpt from "The Most Dangerous Game,” by Richard Connell.


His foot touched the protruding bough that was the trigger. Even as he touched it, the general sensed his danger and leaped back with the agility of an ape. But he was not quite quick enough; the dead tree, delicately adjusted to rest on the cut living one, crashed down and struck the general a glancing blow on the shoulder as it fell; but for his alertness, he must have been smashed beneath it. He staggered, but he did not fall; nor did he drop his revolver. He stood there, rubbing his injured shoulder, and Rainsford, with fear again gripping his heart, heard the general's mocking laugh ring through the jungle.


Compare the film adaptation of the scene to the text.


Which analysis best explains the effect of adding the female character to the scene in the film adaptation?


She advances the plot. Having her run through the jungle moves the events of the story along.

She serves a practical function. Using her bracelet to create the trap makes it more realistic to the audience.

She raises the stakes. Giving the audience another character to care about increases the suspense level.

She balances the film by providing a woman's perspective of the events that unfold in the jungle

Answers

Answer:

Explanation:

D

All the computers in janet’s school computer lab have the latest version of windows installed, which is?

Answers

All the computers in Janet’s school computer lab have the latest version of windows installed, which is Window 8.

A computer is a digital electronic machine that can be programmed to automatically perform a sequence of arithmetic or logical operations (calculation). Modern computers can perform general sets of operations known as programs. These programs allow computers to perform a wide variety of tasks.

A computer system is a "complete" computer that includes the hardware, operating system (main software) and peripherals needed and used for "full" operation. The term can also refer to a group of computers that are connected and work together, such as a computer network or computer cluster.

Hence, the correct answer is Window 8.

Learn more about Computers on https://brainly.com/question/25817628

#SPJ4

what is a dynamic character

Answers

Answer:

someone who learns a lesson or change as a person.

Which quotations from the texts best support the theme that the way to deal with racism is to stand up to it? Select three options.

“This, friends, is the Welcoming Committee!”
“Lord have mercy, ain’t this the living gall!”
“You got any more to say 'bout how people ought to sit down and talk to each other?”
“Get out of my house, man.”
“What do you think you are going to gain by moving into a neighborhood where you just aren’t wanted?”

Answers

The quotations from the texts that best support the theme that the way to deal with racism is to stand up to it are:

"Lord have mercy, ain't this the living gall!"“You got any more to say 'bout how people ought to sit down and talk to each other?”“Get out of my house, man.”

How to illustrate the information?

Raisin in the Sun is a story that presents the life of a black family that after earning a large sum of money and moves to an upscale neighborhood, populated by white citizens.

This story deals with themes such as class ascension, discrimination, racism, dreams, among others.

The sentences presented above are presented at times when characters need to turn against racism and face it in order to get rid of it.

Learn more about theme on:

https://brainly.com/question/11600913

#SPJ1

Answer:

B. “Lord have mercy, ain’t this the living gall!”

C. “You got any more to say 'bout how people ought to sit down and talk to each other?”

D. “Get out of my house, man.”

Explanation:

Using Your Sense to Visualize the Poem
Though I am old with wandering
Through hollow lands and hilly lands,
I will find out where she has gone,
And kiss her lips and take her hands;
And walk among long dappled grass,
And pluck till time and times are done,
The silver apples of the moon,
The golden apples of the sun.
-"The Song of Wandering Aengus,"
William Butler Yeats
Which best describes an image of Aengus based on
the first two lines of this stanza?
O Aengus looks unhappy, because he has not found
the girl.
O Aengus looks tired and can no longer climb up and
down.
Aengus looks old from walking everywhere.
Aengus looks worn out from climbing up and down
mountains.

Answers

That which best describes an image of Aengus based on the first two lines of this stanza is:

Aengus looks worn out from climbing up and down mountains.

What is the best description of Aengus?

In these first two lines, we can see that Aengus looks tired and worn out from undergoing stress in the past.

The stress must have been as a result of climbing through hills and mountains.

Learn more about Aengus here:

https://brainly.com/question/8060696

#SPJ1

Please help me!!



Author appeals to the sense of touch in "A Wrinkle in Time."

Author appeals to the sense of sight in "A Wrinkle in Time."

Author appeals to the sense of hearing in "A Wrinkle in Time."

Author appeals to the sense of taste "A Wrinkle in Time."

Author appeals to the sense of smell in "A Wrinkle in Time."

Answers

Answer is the sense of sight

This is the only thing I can think of, i hope it helps.

This is where Meg realizes the blind (referencing the sight sense) are not limited but she is limited instead.

“It was she who was limited by her senses, not the blind beast, for they must have senses of which she could not even dream.”

Meg realizes the bias society has of blind people.

Which of these lines
seems to show a
contradiction in Edwards'
depiction of the character
of God?

Answers

The lines that seem to show a contradiction in Edwards' depiction of the character of God are:

"...Him who has loved them.../ The God that holds you over the pit of hell, abhors you..."

What was Edward's depiction of God's character?

In Edwards's popular sermon, he depicted God as a person who brings swift justice to the wicked.

In these lines, Edward depicted some form of contrast because God was shown as loving his children and abhorring them. So, the lines above are right.

Learn more about Edward's sermon here:

https://brainly.com/question/17203084

#SPJ1

I tell her she’s going bald. she tells me i copy on tests. we’re best friends. read the excerpt from "mericans." "girl. we can’t play with a girl." girl. it’s my brother’s favorite insult now instead of "sissy." "you girl," they yell at each other. "you throw that ball like a girl." which theme best describes the two passages? in all cultures, children playfully engage in complicated games to prove their strength and intelligence. in all cultures, children playfully taunt one another. in all cultures, children engage in sibling rivalry. in all cultures, children playfully engage in proving that one gender is better than the other.

Answers

B) In all cultures, children playfully taunt one another.

The theme that describes the two passages is (B) In all cultures, children playfully taunt one another.

What is a theme?

A theme is the central concept or underlying meaning that a writer explores in a novel, short tale, or other creative work. Characters, environment, dialogue, storyline, or a mix of these aspects can all be used to communicate a story's theme.

It should be understood that a theme is merely the underlying message of a piece of literature. In this instance, the overarching topic that unifies the two sections is the universality of children's playful taunting of one another.

Learn more about theme

brainly.com/question/1160091

#SPJ4

Read the dialogue from Act II, scene iv of Romeo and Juliet.

Romeo: Thou wast never with me for anything when thou wast not here for the goose.

Mercutio: I will bite thee by the ear for that jest.

Romeo: Nay, good goose, bite not.

Mercutio: Thy wit is a very bitter sweeting; it is a most sharp sauce.

Romeo: And is it not then well served in to a sweet goose?

Which word from the conversation best helps the reader understand the mood of the scene?

“bitter,” because this is an angry conversation
“jest,” because this is a teasing conversation
“served,” because this is a loving conversation
“bite,” because this is a frightening conversation

Answers

Answer:

B) “jest,” because this is a teasing conversation.

Explanation:

Using a play on words, Romeo mocks Mercutio by comparing him to a goose.

The word from the conversation that best helps the reader understand the mood of the scene is B. “jest,” because this is a teasing conversation.

What is a dialogue?

It should be noted that a dialogue means the conservation that takes place between the characters in a literary work.

Here, the word from the conversation that best helps the reader understand the mood of the scene is “jest,” because this is a teasing conversation.

Learn more about dialogue on:

brainly.com/question/6950210

#SPJ1

What obstacles has Odysseus faced so far on his road of trials? Check all that apply.

Answers

Answer: Lord Helios, the sun god, has killed Odysseus's men for eating his cattle. His boat has crashed, and the crew is shipwrecked on the Isle of Man.

Explanation:

I was puzzled, and wanted to discuss the matter a little further, but they didn't; so I took my leave, feeling hurt and insulted to be made the butt of what was apparently some kind of a practical joke, and yet obliged to put up with it, not being in circumstances to resent affronts from rich and strong folk.

Answers

The given sentence is from Mark Twain's "The million pound Bank-Note" is and it is implied that Poor people were expected to tolerate any ridicule made by the rich.

Inside the envelope is a single unique one million pound sterling note. Unbeknownst to him, Henry is the subject of a bet: Brother B believes that simply holding this symbol of wealth, without any other means of support, will allow someone to survive the entire month.

Hence, the correct answer is Poor people were expected to tolerate any ridicule made by the rich.

Learn more about The million pound Bank-Note on https://brainly.com/question/15732537

#SPJ4

what modern medium allows hoaxs to spread quickly and easily to a large number of people

Answers

Answer:

The answer to your question is Social Networking Sites, the internet

Explanation:

I hope this helps and have a good day!

I had so worked upon my imagination as really to believe that about the whole mansion and domain there hung an atmosphere peculiar to themselves and their immediate vicinity -- an atmosphere which had no affinity with the air of heaven, but which had reeked up from the decayed trees, and the gray wall, and the silent tarn -- a pestilent and mystic vapor. Which observation can be made about the narrator

Answers

The Narrator seems unsettled and paranoid.

Paranoia is an irrational and lasting feeling that people are chasing you or that you are the subject of the lasting and intrusive attention of others. This unfounded distrust of others can make it difficult for people with delusions to function socially and maintain close relationships.

Symptoms of various symptoms such as delusional personality disorder, delusional (delusional) disorder, and schizophrenia can be seen.

The cause of paranoia is unknown, but genetics is thought to play a role. Treatment depends on the condition diagnosed as the cause and may include psychotherapy or medication. Delusional symptoms vary from mild to severe

Learn more about Paranoid here: https://brainly.com/question/25960579

#SPJ4


change into indirect speech


1.his daughter said to him,"these are yours socks

2 she said,"i keep my opinions gently in this great occasion "

3 the actress said to him,"you have to work consistently for your success."

4 he said to me," i have not taken your mobile today"

5 they said to us,"we arevlaunching a new programme i your town"

6 i said to him,"this is not your bussiness"

7 rajesh said to karisma,"i cannot spend you money now"


please help me

Answers

Indirect or reported speech requires that we change pronouns, verb tenses, and time or place expressions in order to report what someone has said.

His daughter told him that those were his socks.She said she kept her opinions gently in that great occasion.The actress said to him that he had to work consistently for his success.He told me that he had not taken my mobile that day.They said to us that they were launching a new program in our town.I said to him that that was not his business.Rajesh said to Karisma that he could not spend her money then.

What is indirect speech?

Indirect or reported speech happens when we retell what someone has said in our own words. That means that, rather than repeating things exactly as they were said, we make some changes. Some examples of those changes are:

Verb tenses change into their past form.Pronouns change according to who said what to whom.Time and place expressions change to indicate that the actions took place in the past.

Let's take sentence 4 as an example. Notice the changes that must be done to rewrite it in indirect speech:

Have not --> had notYour --> my (because he said it to me, so he was talking about my phone)Today --> that day

Thus:

Direct speech: He said to me, "I have not taken your mobile today."Indirect speech: He told me that he had not taken my mobile that day.

Learn more about indirect speech here:

https://brainly.com/question/15886943

#SPJ1

information that is put into a system or machine so that it can operate ​

Answers

Answer:

Information that is put into a system or machine so that it can operate is data.

data. data is raw and unprocessed info that can be made to be useful

*Ay, Yoyo, you are going to be the one to bring our name be
What can be inferred about the character who is
to the headlights in this country! That is a beautiful,
speaking in this passage, based on her nonstandard
beautiful speech I want for your father to hear it before
English speech?
he goes to sleep. Then I will type it for you, all right?"
O She is not educated.
-*Daughter of Invention,"
Julia Alvarez
O She does not speak any English.
O She only speaks English to her daughter.
O English is not her first language.
Done


answer: english is not her first language

Answers

Answer:

English is not her first language

Answer:

What does the mother’s language reveal?

✔ She is eager to try English phrases.

What does the mother mean to express about her daughter Yoyo?

✔ She is proud and anticipates success.

Explanation:

Which theme is best reinforced by the excerpt?

Answers

Answer: the third

Explanation:

(100points) i wrote this short essay but the teacher wants me to follow this template. can someone write me the essay following it. first picture is the template second is what i wrote.

Answers

Essay writing is given to students in order to test their writing and reading skills.

How to write an essay?

Based on the information given, the way to write the essay will be given. Firstly, it's important to decide on your topic.

Research should be done on the topic and create an essay outline. Set your argument in the introduction and develop it with evidence.

Finally, check the content, grammar, formatting, and spelling, of your essay.

Learn more about essays on:

brainly.com/question/24799048

#SPJ1

What mistake did George make?

He laughed when the cat sat on the bench.
He was ashamed of what he had done.
He disobeyed and disappointed Papa.


Info in image (please explain your reason why, so I know your right)

Answers

Answer: He disobeyed and disappointed Papa.

Explanation: Papa asked George to dig irrigation ditches but instead George went on a boat ride with his friends.

Which lines indicate that the speaker is concerned about what others think of him? my morning coat, my collar mounting firmly to the chin, my necktie rich and modest, but asserted by a simple pin— in a minute there is time for decisions and revisions which a minute will reverse. with a bald spot in the middle of my hair— [they will say: "how his hair is growing thin!"] and indeed there will be time to wonder, "do i dare?" and, "do i dare?"

Answers

The following sentences might indicate that the speaker is worried about what other people think:

1) They will comment on how "with a bald patch in the centre of my hair—" and "How his hair is growing thin!"

2) The words "with...thin" most likely indicate that the speaker worries about what other people think of him since he considers what others would say about his thin hair.

3) Because of the others, rather than his own thoughts, he is more concerned about the "bald spot" on his head.

This supports the assertion that the way others see him may have an effect on him.

Learn more about "Prufrock" here:

brainly.com/question/3305595

#SPJ4

Answer:

Its C

Explanation:

Which sentence shows an adverb modifying an adjective? A. Laura wildly searched for her car in the parking lot. B. Kevin sadly gave up on his dreams and became an exterminator. C. You are simply the best. D. I should be there really soon.

Answers

Option B. Kevin sadly gave up on his dreams and became an exterminator this sentence shows an adverb modifying an adjective.

An adverb is one of the eight parts of speech that is used to modify a noun, an adjective, and another adverb. The purpose of an adverb is to tell the reader about how, when, and where an action is performed or the quality/degree of action.

From the given options, the sentence in which an adverb is modifying an adjective is the last one (fourth)

In the fourth statement, the adverb is informing about the degree (very) of the adjective (content).

Learn more about adverbs at

https://brainly.com/question/912194

#SPJ1

Other Questions
Fill in the blank: during the 12th century, inspired by ____ culture, islamic civilization developed new iwan form mosque reduction of fixed cost may be achieved by aggregating lots across multiple products, customers, or suppliers. T/F 5. What number does the model below best represent?A. 17/20B. 75%C. 0.80D. 16/20 In a population of 100 people, 58 have brown eyes (the dominant phenotype). What percent of this population is heterozygous? TRUE / FALSE. jane is a loner and often goes to the park wearing camouflage and hides behind trees. Read the passage and choose the correct word for the blank NUMBER 1I watched 'Night at the Museum' last Sunday. It (1) ________ a comedy about a man called Larry. He got a job in a museum and discovered that an ancient stone in the museum could make everything alive (2) ______ night. When three bad men wanted to steal the stone, Larry and his new friends had to save the museum. They were very clever and funny. The (3) _______ was so exciting. I really like this movie because it made me laugh a lot. What a (4) _______ movie!Trnh c Chn thcwere wasbeare suppose x possesses a binomial distribution with n=20 and p=0.1. find the exact value of p(x3) using the table of binomial probabilities. which couple is most at risk for dissatisfaction and relationship dissolution drag each protein to the first b-cell development stage where its expression is observed. true or false Smythe Company is considering the following 5 capital budgeting projects. The cost of capital for all projects is 14% .Project Initial Cost NPV IRR PIA $1,000,000 ($650,000) 10% 0.96B $400,000 $113,000 18% 1.33C $10,000 $2,500 21% 1.52D $2,500,000 $20 15% 1.01E $8,350,000 $515,000 17% 1.44If the projects are MUTUALLY EXCLUSIVE, which project(s) should Smythe accept? (Note: it is possible that more than one project should be accepted. You must check all that apply to receive credit - this is an all or nothing question. That is if they should accept projects A and B and you check only A or only B or if you also check C, your answer will be marked wrong).Project AProject BProject CProject DProject E explore smiths complex relationship to writing. describe her process. why is smith interested in the continental drift club? what is the significance of memory or remembrance for smith? how do astronomers now explain the fact that the energy emitting regions for quasars are so small? Sleep deprivation increases levels of the hunger-arousing hormone...... a. melatonin b. ghrelin c. leptin d. serotonin. What is the maximum possible height that a roller coaster could reach, without any propulsion, when a speed of 65. 0 m/s is reached before the start of a hill? Ignore any type of friction. _____ are digital electronic circuits distinguished by 2 values of intrest. Why should goals be set for a group discussion?a. to limit who participates in the discussion b. to ensure that there are no discussion rules c. to form an opinion before the discussion d. to establish a purpose for the discussion under which type of lease does the lessee obtain the rights to use leased property for a limited period of time and treat amounts paid as expense? PLEASE HELPLPPPP! All life that we know of is based on carbon. Carbon's ability to form many chemical bonds is an important characteristic that allows it to form the basis of life. Identify two other elements that can probably also form a large number of bonds and that probably have similar properties to carbon. Explain your answer. how many chirality centers are present in trans cinnamic acid? does cinnamic acid exist in any stereoisomeric form? if so how many stereoisomers are expected for cinnamic acid? Residual income:a. is the ROI percentage multiplied by average operating assets.b. is the net operating income earned above a certain minimum required return on sales.c. is the net operating income earned above a certain minimum required return on average operating assets.d. will always be greater than zero.