Key Stage 3 (KS3) Biology Practice Test – Exam Prep & Study Guide

The three major components of the circulatory system are indeed the heart, arteries, and veins. The heart serves as the central pump that drives the circulation of blood throughout the body. It generates the force needed to propel blood into the arteries, which carry oxygen-rich blood away from the heart to the body's tissues. Veins, on the other hand, are responsible for returning deoxygenated blood back to the heart. This system functions together to ensure efficient transport of nutrients, oxygen, carbon dioxide, and waste products, playing a vital role in maintaining homeostasis within the body.

The other combinations listed do not fully encompass the core structure of the circulatory system or include components that are not primary to its function—like lungs, which are part of the respiratory system, or kidneys, which are involved in filtration and waste management rather than direct circulation.