There are 8 characteristics that make living things different from non living things

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

I’m doing some practice exam questions for biology, and i’m not sure how to do these 3 parts to the question.

What is the next step in muscle contraction after the actin changes shape