Final answer:
An adaptation is a heritable trait that improves an organism's ability to survive and reproduce in its environment, such as webbed feet in platypuses for swimming or the snow leopard's thick fur for cold climates. Option a.
Step-by-step explanation:
The correct answer to the question is a) Adaptation. An adaptation is a heritable trait that enhances the survival and reproduction of organisms by allowing them to become better suited to their environment.
This process is a result of evolution through natural selection, continually shaping populations so that the organisms can maintain or improve their 'fit' within their habitats.
As an example, a platypus has webbed feet which serve as an adaptation for effective swimming. Another instance is the snow leopard, which has thick fur that acts as an adaptation for surviving in cold environments. Additionally, a cheetah's impressive speed is an adaptation that enhances its ability to catch prey.
So option a.