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• Assertion (A) is True: Morgan and his group found that when two genes in a dihybrid cross were situated on the same chromosome, the proportion of parental gene combinations was much higher than the non-parental type. This physical association of genes is called linkage, and for such genes, Mendel's law of independent assortment does not hold true .
• Reason (R) is False: Closely located genes are tightly linked and show very low recombination; they do not assort independently. They tend to be inherited together . Ideally, only distantly located genes on the same chromosome or genes on different chromosomes assort independently.