During prophase I of meiosis, homologous chromosomes pair up to form a tetrad in a process called:

• A. Independent assortment
• B. Crossing over
• C. Synapsis
• D. Segregation

Answer: (C)

Verified step by step guidance

1. Understand that meiosis is a type of cell division that reduces the chromosome number by half, producing four haploid cells. It consists of two stages: Meiosis I and Meiosis II.
2. Focus on Prophase I of Meiosis I, where homologous chromosomes (one from each parent) pair up. This pairing is a key event in meiosis and is essential for genetic diversity.
3. Learn that the process of homologous chromosomes pairing up is called 'synapsis.' During synapsis, the chromosomes align closely along their lengths to form a structure called a tetrad (four chromatids).
4. Differentiate synapsis from other terms: 'Independent assortment' refers to the random distribution of homologous chromosomes during metaphase I, 'crossing over' is the exchange of genetic material between chromatids, and 'segregation' refers to the separation of homologous chromosomes during anaphase I.
5. Conclude that the correct answer to the question is 'Synapsis,' as it specifically describes the pairing of homologous chromosomes during prophase I of meiosis.