2. Which of the following wrap around axons to form a myelin sheath? A. Astrocytes
B. Ependymal cells
C. Satellite cells
D. Schwann cells

Which of the following is a possible reason for sleep? a) growth b)digestive c)speed d)intelligence

Which ideas did your answer contain? check all that apply. no food for organisms no oxygen in the atmosphere no trees or flowering plants no products based on trees or plants (building materials, medicines, fuels, fibers) no fossil fuels

All but one describes an effect of aging on the digestive system. a) decreased acid secretion b) decreased elasticity of stomach c) capacity to resist damage decreases d) food remains in stomach for less time