What cell organelle immediately identified it as a eukaryote?

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

Nucleic acid certain protein cell membranes certain carbohydrates

In the diagram below, the northern hemisphere would be in what season at position a a.fall b. winter c.summer d.spring