The body system that controls the body by means of chemical molecules called hormones is the endocrine system.

Here's why:

* Hormones: These are chemical messengers produced by glands within the endocrine system.

* Target Cells: Hormones travel through the bloodstream and affect specific target cells in the body.

* Regulation: Hormones regulate a wide variety of bodily functions, including:

* Metabolism

* Growth and development

* Mood and behavior

* Reproduction

* Sleep

* Heart rate

* Blood pressure

Key Components of the Endocrine System:

* Glands: Specialized organs that produce and release hormones (e.g., pituitary gland, thyroid gland, adrenal glands, pancreas).

* Hormones: Chemical messengers that travel through the bloodstream.

* Target Cells: Cells with receptors that bind to specific hormones.

Let me know if you'd like more information about specific hormones or glands within the endocrine system!