Answer:
D. A deer has flat teeth for chewing plants.
Explanation:
Adaptation, which is the ability of an organism to survive changes in its natural environment, can either be structural, behavioral and physiological. Structural adaptation is the possession of a physical or structural feature by an organism to enable it survive or adjust to change.
According to this question, the FLAT TEETH possessed by the deer for chewing plants is an example of structural adaptation because the deer posseses a structural feature (flat teeth) that allows it to feed on plants for survival.