Here's why:

* Structure: Endocrine glands are composed of specialized epithelial cells that are organized into clusters, cords, or follicles.

* Function: These cells produce and secrete hormones directly into the bloodstream, which then travel to target cells throughout the body.

* Examples: The thyroid gland, pituitary gland, and adrenal glands are all examples of multicellular endocrine glands.

While some individual cells in the body can produce hormones (like certain cells in the heart or kidneys), these are not considered true endocrine glands.