Question

the giant panda has six digits on its \hands.\ one of these is a \thumb.\ the thumb is derived from a wrist bone and appears to be a response to a diet rich in bamboo, which requires a thumb to \strip\ the bamboo before eating. the immediate ancestors to this panda will have ______ digits.
1
2
3
4
5

Explanation:

The giant panda's sixth digit (thumb) is a derived adaptation for bamboo feeding. Most bears and the panda's immediate ancestors have 5 digits on their hands, as the extra digit evolved later in response to their bamboo-rich diet. Thus, the immediate ancestors would have 5 digits.

Answer:

5