Answer: (D) paired homologous chromosomes
Step-by-step explanation:
Meiosis I halves the number of chromosomes in the initial cell, so it is called reductive. Meiosis II maintains the number of chromosomes in the early cells, so it is called equational. MeiosisI and II are divided into four phases: prophase, metaphase, anaphase, and telophase.
Prophase I of meiosis is very long and contains important events, so it is divided into 5 subphases: Leptotene, Zygote, Pachyten, Diplotene, and Diakinesis. During the pachytene subphase, the pairing of homologous chromosomes is completed and, in many species, it is possible to identify this pair of homologs, which is called bivalent or tetrad. The term bivalent refers to the presence of two homologous chromosomes and the term tetrad to the existence of four sister chromatids (each chromosome has two sister chromatids).