Which one of the following causes population explosion?

Options

A. Decrease in infant mortality rate and increase in the death rate.
B. Decrease in death rate, maternal mortality rate and infant mortality rate.
C. Decrease in infant mortality rate and decrease in the number of people in reproductive age.
D. Decrease in death and increase in maternal mortality rate.

Answer

To determine which factor causes population explosion, we need to analyze the options provided and understand the concept of population explosion itself.

### Step-by-Step Solution:

1. **Understanding Population Explosion**:
- Population explosion refers to a rapid increase in the number of individuals in a population. This often occurs when the birth rate significantly exceeds the death rate.

2. **Analyzing the Options**:
- **Option 1**: Decrease in infant mortality rate and increase in death rate.
- A decrease in infant mortality rate would typically lead to an increase in population, but an increase in death rate would counteract this effect. Hence, this option is not likely to cause population explosion.

- **Option 2**: Decrease in death rate, maternal mortality rate, and infant mortality rate.
- A decrease in death rates (both maternal and infant) means that more individuals survive to adulthood and reproduce, which contributes to population growth. This option supports the idea of population explosion.

- **Option 3**: Decrease in infant mortality rate and decrease in the number of people in reproductive age.
- While a decrease in infant mortality rate can lead to population growth, a decrease in the number of people in reproductive age would likely reduce the birth rate, counteracting any potential growth. Thus, this option does not lead to population explosion.

- **Option 4**: Increase in death rate and increase in maternal mortality rate.
- Both increases would lead to a decrease in population growth, as more individuals would die. This option does not contribute to population explosion.

3. **Conclusion**:
- The correct answer is **Option 2**: Decrease in death rate, maternal mortality rate, and infant mortality rate. This combination leads to higher survival rates and ultimately contributes to population explosion.