At which stage are the bivalents formed during meiosis?

Bivalents, also known as tetrads, are formed during Prophase I of meiosis. This stage is crucial as it involves the pairing of homologous chromosomes, where each chromosome consists of two sister chromatids. During Prophase I, the chromosomes condense and become visible under a microscope, and the homologous chromosomes align closely together to form bivalents through a process called synapsis. This is essential for crossing over or genetic recombination, which occurs at this stage and contributes to genetic diversity in the resulting gametes.

Understanding that Prophase I is the stage where this pairing occurs emphasizes its importance in the overall process of meiosis, setting the stage for the subsequent stages where these bivalents will segregate into daughter cells.