Which disease damages the human immune system leaving the body open to certain infectious agents?

People who exercise for an hour may have lower cholesterol levels. is that a statement? a law? or a hypothesis?

There are specialized producers that live in warm water vents deep in the ocean. these producers do not per-form from photosynthesis, but instead perform a similar process with iron and other chemicals. why do you think these producers use this process instead of photosynthesis?

Describe the function of the endomembrane system? what organelles are involved?