In idiogram , chromosomes of an organism are arranged according to their :

Options

A. Increasing size
B. Decreasing size
C. Position of centromere
D. Number of chromosomes

Answer

To answer the question "In idiogram, chromosomes of an organism are arranged according to their:", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Term "Idiogram":**
- An idiogram is a graphical representation of the chromosomes of an organism, often referred to as a karyotype. It visually depicts the number and structure of chromosomes.

**Hint:** Remember that an idiogram is related to the visual representation of chromosomes.

2. **Identifying the Arrangement Criteria:**
- The chromosomes in an idiogram are arranged based on specific criteria. The most common arrangement is by size.

**Hint:** Think about how we categorize objects; size is a common method.

3. **Determining the Order of Arrangement:**
- In an idiogram, chromosomes are typically arranged in decreasing order of size. This means that the largest chromosome is placed first, followed by smaller chromosomes.

**Hint:** Visualize a staircase where the largest step is at the top and the steps decrease in size as you go down.

4. **Eliminating Incorrect Options:**
- The arrangement is not based on increasing size, the position of the centromere, or the number of chromosomes. While these aspects may be noted, they do not dictate the order in an idiogram.

**Hint:** Consider what factors are typically used for classification and which ones are not relevant in this context.

5. **Final Conclusion:**
- Therefore, the correct answer to the question is that in an idiogram, chromosomes are arranged according to their **decreasing size**.

### Final Answer:
In an idiogram, chromosomes of an organism are arranged according to their **decreasing size**.