Breathing is the process of moving air into and out of the lungs. The process depends on a muscle called the diaphragm. This is a large, sheet-like muscle below the lungs. Inhaling, or breathing in, occurs when the diaphragm muscle tightens. This increases the size of the chest. This too decreases air pressure inside the lungs. This action allows air and gases to enter the lungs. Exhaling, or breathing out, occurs when the diaphragm muscle relaxes. This decreases the size of the chest. This increases air pressure inside the lungs. This action allows for air to leave the lungs. When you inhale, air enters the respiratory system through your nose and ends up in your lungs, where gas exchange with the blood takes place. What happens to the air along the way? In the nose, mucus and hairs trap any dust or other particles in the air. The air is also warmed and moistened. Next, air passes through a passageway that is connected to the windpipe. The air then finds its way to the lungs. In the chest, the windpipe splits so that air enters both the right and left lung.

Question: "What is happening when your chest decreases in size while breathing?"

Response: "Exhaling"

A: yes

Take a look at this train in Figure 1.11. It looks very futuristic. What do you notice about it? Did you notice that the train has no wheels? How can a train have no wheels? It doesn't need wheels. It actually floats, or levitates, just above the track. Magnets enable the train to do this. This is not a normal train. This is a maglev train. The word maglev stands for magnetic levitation. Because it has no wheels, there is no friction. Some magnets hold the train up. Other magnets are used to move the train forward. This train can go very fast. It can reach speeds up to 480 kilometers (300 miles) per hour! Magnets are pretty cool. What exactly is a magnet? How is it able to exert such force?

Question: "What do you observe about the train in Figure 1.11?"

Response: "It has no wheels"

A: yes

Captured Moments by Will Shetterly I remember Papa's stopbox, a teal blue Tiempo Capturado that Mama brought home for his birthday. It was huge and inefficient, and she should never have spent so many pesos on a toy, but Papa would not let her return it. He used it to preserve baby tomatoes, cucumbers, and strawberries in translucent cubes that he stored in the pantry for spring-time meals in the middle of winter. Mama kept her mink jacket, a family hand-me-down, safe from time in a stopbox, and lent the capturador to my uncle for his stamp collection. Sometimes they would let us little ones to seal a treasured toy or a last piece of birthday cake until we begged them for its release, usually a few hours after enclosing it. When my father died, a year after my mother, my sisters and I cleaned out their apartment. We found our baby shoes protected in stopboxes. I took mine home, where they sat above my computer while I worked on my first play. One night when I did not believe love had ever existed for anyone, I used my own capturador, a sleek titanium Sanyo Tardar Ahora, to undo the stopbox. Bringing my face close to the shoes, I breathed deeply of air that my parents had trapped while closing up that symbol of their love for me. The instant would have been improved had my baby shoes been cleaned before they were encased. But as soon as I coughed, I laughed, and I did not try to kill myself that night.

Question: "Who would not let her return the toys?"

Response: "President"

A:
no