Pick from:
1). natural predators;
2). seasons;
3). Abnormal cell growth;
4). liver cancer;
5). insects;
6). chickenpox;
7). influenza;
8). sunlight;
Q: Fact 1: Having no natural predators increases population size. Fact 2: Population size is a function of natality and mortality. Given the two facts above, having what is a cause of mortality?
A:
1).