Question

glands, such as the thyroid, that secrete their products directly into the blood are classified as ______________ glands.

exocrine

sebaceous

endocrine

ceruminous

Explanation:

Endocrine glands secrete hormones directly into the bloodstream. The thyroid gland is an example of an endocrine gland. Exocrine glands secrete substances through ducts, sebaceous glands secrete sebum onto the skin surface, and ceruminous glands secrete ear - wax.

Answer:

C. endocrine