Question

1. the text says that humans give off light. so why cant we see this light?
2. name two things that the alveoli do.
3. how does acid help digestion?
4. why is blinking important?
5. name one reason that eating fat is important.
6. explain how muscles must work in pairs.

Explanation:

1. Humans emit ultra - weak light in the form of biophotons, but the intensity is too low for the human eye to detect.
2. Alveoli allow oxygen to enter the blood and carbon dioxide to leave the blood. They also help with gas exchange in the lungs.
3. Acid in the stomach helps digestion by breaking down large food particles, activating digestive enzymes (like pepsinogen to pepsin), and killing bacteria.
4. Blinking is important as it spreads tears across the eye surface to keep it moist, clean, and protected, and also helps to refresh the cornea with oxygen.
5. Eating fat is important because it is a source of energy, helps in the absorption of fat - soluble vitamins (A, D, E, K), and provides essential fatty acids.
6. Muscles work in pairs because one muscle in the pair contracts while the other relaxes. For example, in the biceps - triceps pair, when the biceps contracts to flex the arm, the triceps relaxes, and vice - versa for extending the arm.

Answer:

1. The light humans give off is ultra - weak and below the detection threshold of the human eye.
2. Facilitate gas exchange; help oxygen enter and carbon dioxide leave the blood.
3. Breaks down food particles, activates enzymes, kills bacteria.
4. Spreads tears, keeps eye moist and protected, refreshes cornea.
5. Source of energy/ Helps absorb fat - soluble vitamins/ Provides essential fatty acids.
6. One contracts while the other relaxes for movement like flexion and extension.