What is the primary purpose of hormones in the body?

The primary purpose of hormones in the body is to carry messages through the blood, which is accurately represented by the selected answer. Hormones are chemical messengers secreted by glands in the endocrine system. They travel through the bloodstream to target organs and tissues, where they trigger specific physiological responses. This communication system helps regulate various bodily functions including growth, metabolism, immune responses, and mood.

While options such as providing structural support or transporting oxygen in the blood refer to functions performed by proteins or cells (like hemoglobin in red blood cells), they do not fall under the role of hormones. Facilitating digestion involves not only hormones but also enzymes and other processes, making it a broader function than what hormones directly handle. Hormones indeed play a significant role in digestion by signaling the release of digestive enzymes, but their primary function remains communication throughout the body.