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 helps 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.

1. Which line shows the main idea of the bolded paragraph?

We yawn when we get tired as a way to encourage our brains
When you yawn, your jaw muscles get stretched
Also a deep breath during the yawn forces spinal fluid and blood down
The cool air then cools down these fluids

2. Which line shows the main idea of the bolded paragraph?

Yawning is a form of communication
Yawning seems to spread from person to person
Scientists are not yet sure what exactly the message is
People who have more social empathy are more likely to start yawning

1. read the following excerpt from franklin d. roosevelt's "fireside chat 19":

on the other side of the picture, we must learn also to know that guerilla warfare against the germans in, let us say serbia or norway, us; that a successful russian offensive against the germans us; and that british successes on land or sea in any part of the world strengthen our hands.

remember always that germany and italy, regardless of any formal declaration of war, consider themselves at war with the united states at this moment just as much as they consider themselves at war with britain or russia. and germany puts all the other republics of the americas into the same category of enemies. the people of our sister republics of this hemisphere can be honored by that fact.  

the true goal we seek is far above and beyond the ugly field of battle. when we resort to force, as now we must, we are determined that this force shall be directed toward ultimate good as well as against immediate evil. we americans are not destroyers — we are builders.

analyze the effectiveness of this excerpt. how does it function within the speech as a whole? how does the structure of the excerpt to convey the speech's purpose and key points? support your argument with evidence from the speech. (10 points)

to kill a mockingbird basically is about a lawyer who goes against everything in a racist society like at the time of this novel, to defend a black man accused of sexual abuse. in the bible there are cases like that of joseph, who was accused by the woman of potifar, for a crime similar to that of tim robbinson, of that novel (genesis 39: 1-20). at this point we see that god also provides the escape to joseph, who was accused unjustly, but in his time, and through his attitude, his faith was not shaken, and god provided the solution. the perspective of god also written in the bible and not pay evil with evil. (ephesians 4: 32, 1 thessalonians 5: 15, 1 peter 3: 9). atticus, the lawyer, demonstrated during this lee novel, empathy, love of neighbor, understood the situation of this accused man. he went against everything in that society, and stood in favor of that man, for the injustice committed. this shows the empathy, the love taught by christ, in some passages that speak of love and justice in the sermon of the beatitudes (especially verses 6 and 7 of matthew 5).

this question is grammatically incorrect and is illegible to me so i can not answer.