The endocrine glands that produce the steroid hormones, such as the gonads and adrenal cortex, arise from the mesoderm. In contrast, endocrine glands that arise from the endoderm and ectoderm produce the amine, peptide, and protein hormones. Because the endocrine glands play pivotal roles both in reproduction and in development, it seems plausible to extend the role of the endocrine system to account for the progressive changes in body structure and function that occur with aging. changes occur that affect the endocrine system, sometimes altering the production, secretion, and catabolism of hormones. For example, the structure of the anterior pituitary gland changes as vascularization decreases and the connective tissue content increases with increasing age. This restructuring affects the gland’s hormone production. For example, the amount of human growth hormone that is produced declines with age, resulting in the reduced muscle mass commonly observed in the elderly.
A peer is someone who is the same age as you, and they do not have to even know you. You might be friends, you might not. They might be a student that's in the same grade as you.
basically, a peer is a student that is around your age.
