What is the main purpose of hormones released by endocrine glands?

The main purpose of hormones released by endocrine glands is to trigger physical responses in target cells. Hormones are chemical messengers that travel through the bloodstream to specific organs or cells where they bind to receptors and elicit a response. This mechanism allows for the regulation of various physiological processes, including growth, metabolism, reproduction, and stress responses.

For example, insulin, a hormone produced by the pancreas, facilitates glucose uptake by cells, thereby regulating blood sugar levels. Similarly, adrenaline increases heart rate and energy availability during stress situations. The targeted nature of hormone action is fundamental to the endocrine system's ability to coordinate complex biological functions throughout the body.

While temperature regulation, protection against pathogens, and digestion involve hormonal influence, they are not the primary function of hormones in the broader context of the endocrine system. Hormones can influence these processes, but their main role is to initiate and manage responses at the cellular level in various organs, highlighting the significance of option B.