The dermis is the inner layer of skin. The dermis has blood vessels and nerve endings. The nerve endings explain why your skin is sensitive. You can sense pain, pressure, and temperature. You cut your finger and it starts to bleed. What has happened? If your skin bleeds, it means you have cut the dermis layer and damaged blood vessels. The cut really hurts. It hurts because of the nerve endings in this skin layer. The dermis also contains hair follicles and two types of glands. Hair follicles are structures where hairs originate. Each hair grows out of a follicle. Hair passes up through the epidermis. It then extends above the skin surface. Oil glands produce an oily substance. The oil is secreted into hair follicles.

Question: "Why is the dermis a very important part of your skin makeup?"

OPTIONS:
- no
- yes

Answer: "The dermis has blood vessels and nerve endings"

Response: yes

Howland talked but little on their way back to camp. The scene that he had just witnessed affected him strangely; it stirred once more within him all of his old ambition, all of his old enthusiasm, and yet neither found voice in words. He was glad when the dinner was over at Thorne's, and with the going of the mail sledge and the senior engineer there came over him a still deeper sense of joy. Now _he_ was in charge, it was _his_ road from that hour on. He crushed MacDonald's hand in a grip that meant more than words when they parted. In his own cabin he threw off his coat and hat, lighted his pipe, and tried to realize just what this all meant for him. He was in charge--in charge of the greatest railroad building job on earth--_he_, Jack Howland, who less than twenty years ago was a barefooted, half-starved urchin peddling papers in the streets where he was now famous! And now what was this black thing that had come up to threaten his chances just as he had about won his great fight? He clenched his hands as he thought again of what had already happened--the cowardly attempt on his life, the warnings, and his blood boiled to fever heat. That night--after he had seen Meleese--he would know what to do. But he would not be driven away, as Gregson and Thorne had been driven. He was determined on that.

Question: "How did Jack feel after dinner and why did he feel this way?"

OPTIONS:
- no
- yes

Answer: "Jack was unhappy because he lost his job"

Response: no

If you have a mass of 50 kg on Earth, what is your weight in newtons? An object with more mass is pulled by gravity with greater force. Mass and weight are closely related. However, the weight of an object can change if the force of gravity changes. On Earth, the force of gravity is the same everywhere. So how does the force of gravity change? It doesnt if you stay on Earth. What if we travel to another planet or moon in our solar system? Look at the photo of astronaut Edwin E. Aldrin Jr. taken by fellow astronaut Neil Armstrong in the Figure. They were the first humans to walk on the moon. An astronaut weighs less on the moon than he would on Earth. This is because the moons gravity is weaker than Earths. The astronauts mass, on the other hand, did not change. He still contained the same amount of matter on the moon as he did on Earth. If the astronaut weighed 175 pounds on Earth, he would have weighed only 29 pounds on the moon. If his mass on Earth was 80 kg, what would his mass have been on the moon? [Figure 3]

Question: "When does the force of gravity change"

OPTIONS:
- no
- yes

Answer: "When the weight changes"

Response: no

What if you could drain all of Earths oceans? What would it look like? You might be really surprised. You see that the surface has two main features. It has continents and ocean basins. Continents are large land areas. These are the areas that are mostly above sea level. Ocean basins extend from the edges of continents. They include the ocean floor and Earths deep ocean trenches. You will also notice the ocean floor is not flat. It too has many Continents are much older than ocean basins. Some rocks on the continents are billions of years old. Ocean basins may only be millions of years old. Because the continents are so old, a lot has happened to them! As we view the land around us, we see landforms. Landforms are physical features on Earths surface. These features change over time, but how? There are actually two types of forces at work.

Question: "What are continents?"

OPTIONS:
- no
- yes

Answer: "Ocean floor"

Response:
no