Segregation of Mendelian factors (no linkage, no crossing over) occurs during:

Explanation

Let's go through each option individually and explain why the correct option is A, which is Anaphase I. a) Anaphase I: In meiosis, Anaphase I is the stage during which the segregation of Mendelian factors (also known as alleles or genes) occurs. During Anaphase I, the paired homologous chromosomes separate and move towards opposite poles of the cell. This separation is called disjunction. As a result, each daughter cell receives one randomly selected homologous chromosome from each pair. This random assortment of chromosomes ensures the independent segregation of different alleles carried on each chromosome, leading to genetic diversity in the resulting gametes. b) Anaphase II: Anaphase II is the stage that occurs during the second round of cell division in meiosis, specifically in the process of meiosis II. In this stage, the sister chromatids separate and move towards opposite poles of the cell. However, this stage is not involved in the segregation of Mendelian factors because the sister chromatids are already identical copies of each other. Anaphase II ensures that each daughter cell receives a complete set of chromosomes. c) Diplotene: Diplotene is a stage that occurs during prophase I of meiosis. It is characterized by the pairing of homologous chromosomes and the formation of a structure called a bivalent or tetrad. During this stage, genetic recombination or crossing over may occur, where sections of homologous chromosomes exchange genetic material. However, the segregation of Mendelian factors does not occur during diplotene. Instead, diplotene is involved in the exchange of genetic material between homologous chromosomes. d) Metaphase I: Metaphase I is the stage that follows prophase I in meiosis. During metaphase I, the bivalents align at the equator of the cell. The homologous chromosomes within each bivalent are paired, but the bivalents themselves are arranged randomly at the metaphase plate. While metaphase I is important for the proper alignment and distribution of homologous chromosomes, it is not the stage where the segregation of Mendelian factors occurs. The segregation of homologous chromosomes occurs during Anaphase I. In summary, the correct option is a) Anaphase I, as it is the stage where the segregation of Mendelian factors takes place.