Final answer:
Complementary surfaces are crucial for efficient molecular interactions, precise cellular communication, and proper structural assembly within biological systems.
Step-by-step explanation:
Complementary surfaces are important for a variety of reasons in biological systems. Firstly, they allow for efficient interaction and binding between molecules, such as enzymes and substrates or antibodies and antigens. Secondly, complementary surfaces facilitate precise cellular communication and signaling which is vital for processes like immune response and hormone action.