Given a scientific question, generate a correct answer to it.

Q: Mixtures that have the same composition throughout are known as what kinds of mixtures?

A: homogeneous
****
Q: What is the outer layer of an axon that acts like a layer of insulation, similar to the plastic that encases an electrical cord?

A: myelin sheath
****
Q: What system of the body is responsible for producing hormones?

A:
endocrine system
****