OPTIONS:
1). competition;
2). Most plants;
3). rocks;
4). A computer;
5). influenza viruses;
6). nothing;
7). peachleaf willow;
8). dust;

Fact 1: Mutation creates new genetic variation in a gene pool. Fact 2: Influenza viruses mutate. Given the two facts above, what can achieve new genetic variation in its gene pool?
Answer:
5).