Answer :
Homologous chromosomes cross over is unique to meiosis and not mitosis.
In meiosis , synapsis (Pairing of homol-ogous chromosome), Cross-ing over (exchange of chromosomal seg-ment bet-ween nos sister chromatids) occurs whi-ch does not occur in mitosis.
Also meiosis is reduct-ional division , the chromo-somal number during meiosis is reduc-ed to half while no such reduct-ion in chromo-somal number occurs during mitosis.
Hence answer is 'Homologous chromo-somes cross over'
Synapsis or synd-esis is the length-wise pairing of homologous chromo-somes. Synapsis mainly occurs during pro-phase I of meiosis I.
A protein complex call-ed the synapton-emal complex con-nects the homol-ogues. The chrom-atids inter-twine, breaking apart and exc-hanging pieces with one other in a pro-cess call-ed crossing-over.
To know more about synapsis click below:
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