OCR GCSE Biology 2025 – 400 Free Practice Questions to Pass the Exam

Collagen is primarily found in connective tissues, which include skin, bone, ligaments, and tendons. It is an essential protein that provides structural support and strength to these tissues. In skin, collagen helps maintain elasticity and firmness, while in bone, it contributes to strength and structure. Ligaments and tendons, which connect bones to each other and muscles to bones respectively, are rich in collagen, enabling them to withstand tension and provide support during movement.

Other tissues mentioned, such as blood and lymph, do not contain collagen in the same structural capacity, as they are fluids responsible for transport and immune functions. Adipose tissue, primarily involved in energy storage, does not have the same need for structural support that collagen provides. Muscle and nerve tissue also lack significant collagen content, as their functions are related to movement and signal transmission rather than structural integrity. Thus, the presence of collagen in skin, bone, ligaments, and tendons explains why this is the correct answer.