Question

bodys system of glands that release their secretions, called hormones, directly into the bloodstream
gi tract
endocrine system
dopamine system
metabolic process
neuroendocrine cell

Explanation:

The endocrine system is a collection of glands that secrete hormones directly into the bloodstream. The GI - tract is related to digestion, the dopamine system is about a specific neurotransmitter, a metabolic process is a general term for chemical reactions in the body, and a neuroendocrine cell is a type of cell, not a system.

Answer:

B. endocrine system