During meiosis I, chromosome number(a)Is reduced to half(b)Doubles up(c)Remains the same(d)Either A or B

During meiosis I, the chromosome number is reduced to half.

Here’s an explanation:

Meiosis Overview: Meiosis is a type of cell division that reduces the chromosome number by half, creating four haploid cells from one diploid cell. This is crucial for sexual reproduction.

Stages of Meiosis I:

Prophase I: Homologous chromosomes pair up and exchange genetic material through crossing over.
Metaphase I: Paired homologous chromosomes align along the metaphase plate.
Anaphase I: Homologous chromosomes are pulled to opposite poles of the cell. Unlike mitosis, sister chromatids remain together.
Telophase I and Cytokinesis: The cell divides into two new cells, each with half the original number of chromosomes.
In meiosis I, homologous chromosomes (each consisting of two sister chromatids) are separated into two cells. Each resulting cell has half the number of chromosomes of the original cell, but each chromosome still consists of two sister chromatids. This halving is what makes the cells haploid.

Therefore, the correct answer is:
(a) Is reduced to half