Science mysteries: why do people yawn?
science has given humans many amazing devices and useful bits of knowledge. we know so much about our bodies and how to stay healthy, for example. we also know how to make machines and devices that make life easy for us. scientists dedicate their lives to knowledge, but even with a lifetime commitment, sometimes scientists fail to find all the answers. one mystery that still remains unsolved is why we yawn-what makes us yawn and what purpose it serves.
recent studies suggest that we yawn when we get tired as a way to encourage our brains. the theory is that yawning cool the brain, allowing it to work more efficiently. according to webmd's article about these studies, when you yawn, your jaw muscles get stretched, increasing blood flow to your neck, face, and head. also a deep breath during the yawn forces spinal fluid and blood down from the brain. the cool air then cools down these fluids.
other scientists believe, however, that yawning is a form of communication. this theory attempts to explain why yawning seems to spread from person to person. this kind of behavior is called "contagious yawning" and carries with it a possible social message. scientists are not yet sure what exactly the message is, but they believe people who have more social empathy are more likely to start yawning when they see someone else yawning.
scientists will continue to investigate the mystery of the yawn. is it a leftover behavior from before humans had language? was it a "hey, i'm sleepy. let's go to sleep" message? or is it really just a way to keep our brains cool? while this behavior still is largely a mystery, one thing is certain: you are probably fighting the urge to yawn right about now.
which word from the first paragraph presents the author's view of scientists? (5 points)

believe

dedicate

yawn

fight

Read the excerpt below from "letter from birmingham jail" and then answer the question below: "my citing the creation of tension as part of the work of the nonviolent resister may sound rather shocking. but i must confess that i am not afraid of the word "tension." i have earnestly opposed violent tension, but there is a type of constructive, nonviolent tension which is necessary for growth. just as socrates felt that it was necessary to create a tension in the mind so that individuals could rise from the bondage of myths and half truths to the unfettered realm of creative analysis and objective appraisal, so must we see the need for nonviolent gadflies to create the kind of tension in society that will men rise from the dark depths of prejudice and racism to the majestic heights of understanding and brotherhood." how does king's repetition of the term "tension" impact the meaning of the text? question 5 options: dr. king says that he is afraid of the word tension and he doesn't think it is necessary. dr. king repeats the word tension to explain how he sees the word as a negative force that discourages change. dr. king repeats the word tension unintentionally, and it doesn't impact the meaning of the text. dr. king repeats the word tension to support how he views the word tension as positive and growth-producing.

Memories of a memory have you ever witnessed something amazing, shocking or surprising and found when describing the event that your story seems to change the more you tell it? have you ever experienced a time when you couldn't really describe something you saw in a way that others could understand? if so, you may understand why some experts think eyewitness testimony is unreliable as evidence in scientific inquiries and trials. new insights into human memory suggest human memories are really a mixture of many non-factual things. first, memory is vague. imagine your room at home or a classroom you see every day. most likely, you could describe the room very generally. you could name the color of the walls, the floors, the decorations. but the image you describe will never be as specific or detailed as if you were looking at the actual room. memory tends to save a blurry image of what we have seen rather than specific details. so when a witness tries to identify someone, her brain may recall that the person was tall, but not be able to say how tall when faced with several tall people. there are lots of different kinds of "tall." second, memory uses general knowledge to fill in gaps. our brains reconstruct events and scenes when we remember something. to do this, our brains use other memories and other stories when there are gaps. for example, one day at a library you go to quite frequently, you witness an argument between a library patron and one of the librarians. later, when telling a friend about the event, your brain may remember a familiar librarian behind the desk rather than the actual participant simply because it is recreating a familiar scene. in effect, your brain is combining memories to you tell the story. third, your memory changes over time. it also changes the more you retell the story. documented cases have shown eyewitnesses adding detail to testimony that could not have been known at the time of the event. research has also shown that the more a witness's account is told, the less accurate it is. you may have noticed this yourself. the next time you are retelling a story, notice what you add, or what your brain wants to add, to the account. you may also notice that you drop certain details from previous tellings of the story. with individual memories all jumbled up with each other, it is hard to believe we ever know anything to be true. did you really break your mother's favorite vase when you were three? was that really your father throwing rocks into the river with you when you were seven? the human brain may be quite remarkable indeed. when it comes to memory, however, we may want to start carrying video cameras if we want to record the true picture. part a and part b below contain one fill-in-the-blank to be used for all three question responses. your complete response must be in the format a, b, c including the letter choice, commas, and a space after the commas. part a: which of the following best explains why memories from childhood are unreliable? fill in blank 1 using a, b, or c. our brains add details and general knowledge to childhood memories. our brains are not as reliable as video cameras are. our brains create new stories to make the past more interesting. part b select one quotation from the text that supports your answer to part a. add your selection to blank 1 using e, f, or g. but the image you describe will never be as specific or detailed as if you were looking at the actual room. when a witness tries to identify someone, her brain may recall that the person was tall, but not be able to say how tall. to do this, our brains use other memories and other stories when there are gaps. select one quotation from the text that supports your answer to part a. add your selection to blank 1 using h, i, or j. documented cases have shown eyewitnesses adding detail to testimony that could not have been known at the time of the event. with individual memories all jumbled up with each other, it is hard to believe we ever know anything to be true. when it comes to memory, however, we may want to start carrying video cameras if we want to record the true picture answer for blank 1:

Read this example: original work - a novel about a man's struggles to returnhome to his family after spending the past ten yearsfighting in a war.which work would represent a change to the artistic medium of this originalwork? a. a story written about the man's adventures since the warb. a novel that translates the story into another language.c. a painting of the man wishing he was home with his familyd. a book written about the war the man was fighting