A triangular age pyramid has

Options

A. declining population
B. increasing population
C. stable population
D. fluctuating population

Answer

### Step-by-Step Solution:

1. **Understanding Age Pyramids**: An age pyramid, also known as a population pyramid, visually represents the distribution of various age groups in a population. It helps in understanding the growth trends of a population.

2. **Identifying Types of Age Pyramids**: There are three main types of age pyramids: expanding, stable, and declining. Each type has a distinct shape and indicates different population dynamics.

3. **Expanding Population (Triangular Shape)**:
- In an expanding population, the number of individuals in the pre-reproductive age group (typically ages 0-14) is greater than those in the reproductive age group (ages 15-49) and the post-reproductive age group (ages 50 and above).
- This results in a triangular shape, where the base (pre-reproductive) is wider than the middle (reproductive) and the top (post-reproductive).

4. **Stable Population**:
- In a stable population, the age groups are almost equal in number, leading to a more rectangular shape. The distribution of individuals across the age groups is balanced.

5. **Declining Population**:
- In a declining population, the number of individuals in the pre-reproductive age group is less than in the post-reproductive age group. This results in an irregular shape that narrows at the base.

6. **Conclusion**: Therefore, a triangular age pyramid specifically indicates an expanding population, where the pre-reproductive age group is larger than the reproductive and post-reproductive age groups.