D
Below is a question with multiple-choice answers. Choose the correct option based on your reasoning.

### Question:
Scientists found a fossil of an elephant in the African savanna. It has much longer tusks and is much larger than elephant species presently inhabiting the area. This elephant fossil most likely reveals

### Choices:
A. the diet of early elephants.
B. that elephants travel in herds.
C. the function of the trunk of the elephant.
D. that physical changes occurred in elephants over time.

### Answer:
