Which phase of meiosis is characterized by the alignment of chromosomes at the center of the cell? 

During meiosis I, the phase characterized by the alignment of homologous chromosomes at the center of the cell is called metaphase I. In this phase, homologous pairs of chromosomes (tetrads) line up along the metaphase plate, which is located at the equator of the cell. The paired chromosomes are held together by structures called chiasmata, which are the sites of genetic recombination.

Once the homologous pairs are properly aligned at the metaphase plate, they are separated during the subsequent phases of meiosis I. This separation is essential for generating genetic diversity in sexually reproducing organisms, as it creates new combinations of alleles on different chromosomes.