I looked it up and it should be D. Nerve cells :)
Answer:
The answer is D.
Explanation:
The friction of the brake rubbing the rim of the front tire causes the bike to slow down and stop.
Coal and natural gas are examples of A) nonrenewable resources. Those are resources that cannot be used again and again and can run out if their supply runs out.
Answer:
1. Providing structure --> Collagen makes skin strong yet flexible.
2. Maintaining homeostasis --> Insulin controls the concentration of sugar in the blood.
3. Fighting Disease --> IgA prevents the buildup of viruses and bacteria in the gut.
4. regulating chemical reactions --> Pepsin works in the stomach to speed up the breakdown of food.
