Answer:
Crossing over is the phenomenon by which homologous chromosomes exchange DNA segments between them during the process of meiosis.
If crossing over did not occur, there will be no genetic variation among parents and offsprings.
If the process of meiosis did not occur, there will be lesser chances of genetic variations to occur. Each chromosome will be either from the father or the mother with no genetic diversity present in it. As a result, genetic diversity will reduce.
