Which system contains glands that affect the growth, development, sexual activities, and health of the entire body?

The endocrine system is the correct answer because it consists of a network of glands that produce and secrete hormones directly into the bloodstream. These hormones play a crucial role in regulating a wide array of bodily functions, including growth, metabolism, sexual development, and overall health.

For instance, the pituitary gland, often referred to as the "master gland," releases hormones that influence other glands in the endocrine system, thereby controlling a variety of processes throughout the body. The thyroid gland affects metabolism and energy levels, while the adrenal glands are involved in the body’s response to stress. Additionally, sex hormones from glands such as the ovaries and testes govern sexual development and function.

In contrast, the muscular system is responsible for movement and stability; the nervous system controls and coordinates body activities through electrical signals; and the circulatory system is essential for transporting blood, nutrients, and oxygen throughout the body. While all these systems are interconnected and vital for overall health, it is the endocrine system that specifically governs hormonal regulation affecting growth and development comprehensively.