AP BIOLOGY

Detailed explanation-1: -During zygotene, homologous chromosomes form tetrads by the process of synapsis (pairing of homologous chromosomes). Formation of synaptonemal complex is also seen during this stage.

Detailed explanation-2: -Tetrad formation occurs during the zygotene stage of meiotic prophase. It is a meiotic-specific process. Homologous chromosomes are DNA fragments within a diploid organism of the same size one from each parental source.

Detailed explanation-3: -In prophase I of meiosis, the homologous chromosomes form the tetrads.

Detailed explanation-4: -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-5: -During prophase I, homologous chromosomes pair and form synapses, a step unique to meiosis. The paired chromosomes are called bivalents, and the formation of chiasmata caused by genetic recombination becomes apparent. Chromosomal condensation allows these to be viewed in the microscope.