In pyramid of numbers, from the lower trophic level to higher trophic level there is progressive

Options

A. Decrease in number and size of organisms
B. Increase in number and size of organisms
C. Decrease in number and increase in size of organisms
D. Increase in number and decrease in size of organisms

Answer

To solve the question regarding the pyramid of numbers and the changes that occur as we move from lower to higher trophic levels, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Trophic Levels**:
- Trophic levels represent the different levels in a food chain, starting from producers (like plants) at the bottom to apex predators at the top.

2. **Identifying Organisms in Each Trophic Level**:
- At the bottom trophic level, we have producers such as grass or plants. These organisms are usually very numerous and small in size.
- The next level consists of primary consumers, such as cows, which feed on the grass. Their numbers are fewer compared to the producers, and they are larger in size.
- Moving up, we have secondary consumers like lions, which feed on the cows. Their numbers are even fewer, and they are larger than the primary consumers.
- Finally, at the top, we have apex predators or scavengers like vultures, which have the least number and are also large in size.

3. **Analyzing the Pattern**:
- As we move from the lower trophic level (producers) to the higher trophic levels (consumers), we observe:
- A **decrease in the number of organisms**: There are many more plants than there are cows, and even fewer lions than cows.
- An **increase in the size of organisms**: The size of the organisms increases as we move up the trophic levels (grass < cow < lion < vulture).

4. **Conclusion**:
- Therefore, the correct answer to the question is that there is a **decrease in number and an increase in size of organisms** as we move from lower to higher trophic levels.

### Final Answer:
- The correct option is: **decrease in number and increase in size of organisms**.