CBSE Class 11-science Answered
During the prophase of meiosis I, homologous chromosomes pair and form synapses, a step unique to meiosis. The paired chromosomes are called bivalents. The bivalent has two chromosomes and four chromatids, with one chromosome coming from each parent.
This step does not occur in mitosis and hence, bivalents are formed only during meiosis and not during mitosis.