Hormones are secreted by:

Correct answer: (d) Endocrine glands

Explanation

Hormones are chemical messengers that regulate growth, metabolism and reproduction.

They are secreted by endocrine glands (pituitary, thyroid, adrenal, pancreas, gonads) directly into the bloodstream, without ducts.

Exocrine glands release enzymes/sweat through ducts, and sebaceous glands secrete oil (sebum), not hormones.