Answer:
b. hormones
Explanation:
"The endocrine system is made up of glands that make hormones. Hormones are the body's chemical messengers. They carry information and instructions from one set of cells to another"
Its has to be A that's just plain common sense
Answer:
Tricuspid valve
Explanation:
The tricuspid valve helps push blood only from the right atrium into the right ventricle
