Correct option (d) Recombinations
Explanation :
Recombination takes place in meiosis but still Meiosis maintains the chromosome number constant. It produces haploid gametes by reducing the chromosome number to half. Crossing over produces new combination of linked genes and is major source of genetic variation.
Also, distribution of bivalents which ts at random in metaphase-I provides the secondary source of genetic variation in the organisms and is essential for speciation and evolution.
