How many chromosomes present in gymnospermic endosperm if leaf has 20 chromosomes ?

Options

A. 6
B. 10
C. 18
D. 24

Answer

To determine the number of chromosomes present in the gymnospermic endosperm when the leaf has 20 chromosomes, we can follow these steps:

### Step 1: Understand the Chromosome Number in Leaves
- The leaf of a plant is a somatic organ and is diploid, which means it has two sets of chromosomes. The diploid number is represented as 2n.

### Step 2: Identify the Diploid Number
- According to the question, the leaf has 20 chromosomes. Therefore, we can set up the equation:
\[ 2n = 20 \]

### Step 3: Calculate the Haploid Number
- To find the haploid number (n), we divide the diploid number by 2:
\[ n = \frac{20}{2} = 10 \]

### Step 4: Understand the Chromosome Number in Gymnospermic Endosperm
- The endosperm in gymnosperms is formed from a haploid megaspore before fertilization, meaning it is also haploid (n).

### Step 5: Conclusion
- Since we have calculated that n = 10, the number of chromosomes present in the gymnospermic endosperm is 10.

### Final Answer
- Therefore, the number of chromosomes in the gymnospermic endosperm is **10**.