Glands secrete hormones that regulate processes such as growth, reproduction, and nutrient use (metabolism) by body cells.

• A. Endocrine system
• B. Nervous system
• C. Integumentary system
• D. Digestive system

Answer: (A)

Glands secrete chemical messengers that travel through the bloodstream to distant targets, coordinating growth, reproduction, and how body cells use nutrients. This describes the endocrine system, whose main job is to regulate many processes throughout the body with hormones. The nervous system mainly uses rapid, direct signaling at synapses, and the other systems listed are primarily involved in protection (integumentary) or digestion and nutrient processing (digestive) rather than widespread hormonal regulation.