AP BIOLOGY

Detailed explanation-1: -During prophase I, the pairs of homologous chromosomes come together to form a tetrad or bivalent, which contains four chromatids. Recombination can occur between any two chromatids within this tetrad structure.

Detailed explanation-2: -Complete answer: Genetic recombination occurs in the Pachytene phase of prophase of meiosis I. So, the correct option is (C). Meiosis-It occurs in the mature diploid reproductive cells in which the nucleus divides twice but the chromosome replicates only once to form four haploid cells.

Detailed explanation-3: -Explanation: The crossing over of homologous chromosomes occurs in prophase I of meiosis. Prophase I of meiosis is characterized by the lining up of homologous chromosomes close together to form a structure known as a tetrad. A tetrad is composed of four chromatids.

Detailed explanation-4: -Genetic variation is increased by meiosis Recombination or crossing over occurs during prophase I. Homologous chromosomes – 1 inherited from each parent – pair along their lengths, gene by gene. Breaks occur along the chromosomes, and they rejoin, trading some of their genes.

Detailed explanation-5: -Crossing over results in an exchange of genetic material between chromosomes that occurs only in prophase I of meiosis. During prophase I, homologous chromosomes (those that are the same, one from the mother and one from the father) pair up.