Which of the following best describes hormones?

Hormones are best described as chemical messengers secreted by glands. This definition captures the essential nature of hormones, emphasizing their role in transmitting signals throughout the body. Produced by various glands within the endocrine system, hormones travel through the bloodstream to target organs or tissues, leading to changes in physiological processes such as metabolism, growth, and mood regulation.

This ability to communicate and cause widespread effects distinguishes hormones from other biological substances. The other options mention elements or substances that do not encompass the broad and systemic functions of hormones. For instance, neurotransmitters, while also chemical signals, operate within the nervous system and are not secreted by glands in the same way hormones are. Additionally, hormones are not specifically proteins that solely enhance physical strength or minerals affecting metabolic rates. Thus, the characterization of hormones as chemical messengers is most accurate and comprehensive, reflecting their critical role in maintaining homeostasis and regulating various body functions.