AP BIOLOGY

Detailed explanation-1: -At the end of prophase I, the pairs are held together only at the chiasmata; they are called tetrads because the four sister chromatids of each pair of homologous chromosomes are now visible.

Detailed explanation-2: -During prophase I, the pairs of homologous chromosomes come together to form a tetrad or bivalent, which contains four chromatids.

Detailed explanation-3: -During prophase I of meiosis I, the condensed homologous chromosomes line up to create tetrads, which are composed of two pairs of sister chromatids. Each homologous pair signs up with the help of proteins, and together they form what is called the synaptonemal complex.

Detailed explanation-4: -Each pair of chromosomes-called a tetrad, or a bivalent-consists of four chromatids.