You are presented with the quiz "What divide more often than normal cells, and grow out of control?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "cancer cells divide more often than normal cells, and grow out of control" and "cancer is an example of a mutation in cells". So, what's the best answer to the question?

1). white blood cells;
2). Most plants;
3). hair cells;
4). skin cells;
5). Smoking;
6). peachleaf willow;
7). mutated cells;
8). cigarettes;
7).