What type of hormone travels through the bloodstream to distant sites in the body?

The correct answer is that circulating hormones travel through the bloodstream to distant sites in the body. These hormones are secreted by glands and enter the systemic circulation, allowing them to reach various target organs and tissues far from their site of production. This mechanism is crucial for coordinating complex physiological responses and regulating processes such as growth, metabolism, and mood.

Circulating hormones include a wide range of substances, such as adrenaline, insulin, and thyroid hormones, which can exert effects on multiple organs throughout the body. Their ability to function at a distance is what differentiates them from local hormones, which act on nearby cells in the same tissue or organ without entering the circulation. Understanding the role of circulating hormones is vital for comprehending how the endocrine system maintains homeostasis and regulates bodily functions.