A system is a group of related parts with specific roles that work together to achieve an observed result. If a body system, such as the digestive system, fails to work properly, what would happen to the organism?

A. The other organ systems would compensate for the defective system.

B. The organism would immediately evolve so the defective system is no longer necessary.

C. The defective system would regenerate into a new, working system.

D. The organism would not be able to function properly.