To determine the size of the group after the mentioned events, we can calculate it step by step:
- Starting group size: 10 members
- Females emigrate: 10 - 4 = 6 members
- Females immigrate: 6 + 2 = 8 members
- Gorillas are born: 8 + 2 = 10 members
- A male dies: 10 - 1 = 9 members
Therefore, the size of the group after all these events is 9.
The correct response is 9.