**Chromosome Number in Endosperm of Pinus**

The endosperm in Pinus is a tissue that provides nourishment to the developing embryo. It is formed as a result of the fusion of a sperm cell with the central cell of the female gametophyte. The central cell of the female gametophyte is the result of a process called double fertilization, where one sperm fertilizes the egg cell to form the embryo, and the other sperm fuses with the central cell to form the endosperm.

The chromosome number in the endosperm of Pinus is determined by the process of double fertilization. In Pinus, the leaf cells and the female gametophyte cells (including the central cell) have a haploid chromosome number of 12. This means that each cell contains 12 chromosomes.

During double fertilization, the sperm cell that fuses with the central cell also contributes its set of chromosomes. Since the sperm cell is haploid, it contains half the number of chromosomes as the leaf cells or female gametophyte cells. Therefore, the sperm cell adds an additional 12 chromosomes to the existing 12 chromosomes in the central cell.

**Explanation of the Correct Answer**

The correct answer is option B, which states that the chromosome number in the endosperm of Pinus is 12 chromosomes. This is because the endosperm is formed as a result of double fertilization, where the sperm cell fuses with the central cell. The sperm cell contributes its set of chromosomes, which is half the number of chromosomes present in the leaf cells or female gametophyte cells. Since the leaf cells of Pinus have a chromosome number of 24, the endosperm will have half that number, which is 12 chromosomes.

Therefore, the chromosome number in the endosperm of Pinus is 12 chromosomes.

In Pinus generally leaf and roots are diploid ...so 2n=24....so the endosperm that is n will be..n=12...that is half of the diploid cell.