AEST Animal Science Specialist Certification Practice Exam

The circulatory system is primarily composed of a network that facilitates the transport of blood, nutrients, gases, and waste products throughout the body. Capillaries, arteries, and veins are integral components of this system.

Capillaries are tiny blood vessels that connect the arterial and venous systems, allowing for the exchange of oxygen, carbon dioxide, and other substances between the blood and tissues. Arteries carry oxygenated blood away from the heart to the various tissues of the body, while veins return deoxygenated blood back to the heart. Together, these structures ensure a continuous flow of blood, critical for maintaining biological functions and overall homeostasis.

In contrast, the other choices contain structures that do not belong to the circulatory system. The lungs and trachea are part of the respiratory system, responsible for gas exchange, while muscles, ligaments, and tendons are components of the musculoskeletal system, essential for movement and support. The intestines, liver, and pancreas are parts of the digestive system, involved in nutrient processing and metabolism. Thus, the selected answer accurately identifies the components that are specifically part of the circulatory system.