Answer:
The correct answer would be conjugation.
Paramecia can reproduce sexually as well as asexually. In the case of paramecium, asexual means include binary fission and sexual reproduction involves the process of conjugation.
Conjugation is the process by which two paramecia unite temporarily and exchange genetic material.
In each paramecium, the micronucleus divides by meiotic division and produces four haploid nuclei out of which only 1 nucleus survives.
The survived nuclei divide with the help if mitotic division and forms two nuclei.
The two paramecia get separated after exchanging one haploid nucleus.
The new haploid nucleus and old haploid nucleus fuse with each other to form a diploid micronucleus.
