Answer:
It increases genetic variation.
Explanation:
Meiosis does not decrease the number of chromosomes nor increase the number of them, it merely splits them.
While it could increase mutations, this might not necesarily be a good thing.
However, it does increase genetic variation, especially during the process where crossing over occurs. Increased genetic variation is beneficial for the population for many reasons like higher resistance to certain diseases. Increasing genetic variation also makes a species look unique from other members of the species.