What is the most common interaction between species?

Epinephrine is a hormone released from the adrenal gland of the body, most often in a stressful situation. it is known as the "fight-or-flight" hormone. one way that it causes a response in the body is to activate receptors on muscle cells. where are these cellular receptors located? a. on the cell membrane b. in the nucleus c. on the cell wall d. around the mitochondria

How does the nervous system affect the excretory system?

14. which of the following codons code for threonine? a. ucg b. ugu c. cga d. aca