Step 1: Understanding meiosis.
Meiosis is the process of cell division that results in the production of gametes. During meiosis I, homologous chromosomes separate, and during meiosis II, the sister chromatids separate.
Step 2: Analyzing the options.
(A) Bivalents are formed in meiosis I: This is correct. During prophase I of meiosis, homologous chromosomes pair up and form bivalents.
(B) Homologous chromosomes separate from each other in meiosis I: This is also correct. During anaphase I of meiosis, homologous chromosomes separate, not sister chromatids.
(C) Sister chromatids are separated from each other in meiosis I: This is incorrect. Sister chromatids separate in meiosis II, not meiosis I.
(D) Each round of chromosome segregation is followed by one round of DNA replication: This is incorrect. DNA replication only occurs before meiosis I, not between meiosis I and II.
Step 3: Conclusion.
The correct answer is (A) Bivalents are formed in meiosis I, as this directly describes a key feature of meiosis I.