Answer:
Option 3: Hotter temperatures during the summer months cause more deaths, and survivors tend to give birth to children that are more resistant to heat.
Step-by-step explanation:
This is because natural selection is the process by which organisms with traits that are better suited to their environment are more likely to survive and reproduce, passing on those traits to their offspring. In this case, the hotter temperatures are selected for individuals who are more resistant to heat. These individuals are more likely to survive and reproduce, passing on their heat resistance genes to their offspring. As a result, the human population will become more resistant to heat over time.