Which of the following factors increase, the size of a population ?

Options

A. natality and immigration
B. natality and mortality
C. mortality and immigration
D. natality and emigration

Answer

To determine which factors increase the size of a population, we need to analyze the terms related to population dynamics. Here's a step-by-step solution:

### Step 1: Understand the Factors Affecting Population Size
There are four main factors that influence the size of a population:
1. Natality
2. Mortality
3. Immigration
4. Emigration

### Step 2: Define Each Factor
- **Natality**: This refers to the number of births in a population during a specific period. An increase in natality means more individuals are being born, which contributes to an increase in population size.

- **Mortality**: This is the number of deaths in a population during a specific period. An increase in mortality means more individuals are dying, which decreases the population size.

- **Immigration**: This refers to the number of individuals of the same species that move into a habitat from elsewhere. An increase in immigration adds individuals to the population, thus increasing its size.

- **Emigration**: This is the number of individuals that leave a habitat to live elsewhere. An increase in emigration means more individuals are leaving, which decreases the population size.

### Step 3: Identify Factors that Increase Population Size
From the definitions:
- **Natality** increases population size.
- **Immigration** also increases population size.
- **Mortality** decreases population size.
- **Emigration** decreases population size.

### Step 4: Conclusion
Therefore, the factors that increase the size of a population are **Natality and Immigration**.

### Final Answer
The correct answer is: **Natality and Immigration**.

---