Answer:
It is both a barrier keeping unwanted things out, and a gate for nutrients to be brought in.
Anaerobic respiration<span> is in muscles. Glucose is not completely broken down, so much less energy is released than during </span>aerobic respiration<span>. There is a build-up of lactic acid in the muscles during vigorous exercise. The lactic acid needs to be oxidised to carbon dioxide and water later.</span>
Answer:
1. B
2. B
3. A
Sorry if any of these are wrong
