Concept:Conjugation in Paramecium is a sexual process that involves micronuclear division and the exchange of genetic material.
Explanation:During conjugation, two Paramecium cells join temporarily and their macronuclei disintegrate.
Each micronucleus divides twice by meiosis, producing four haploid nuclei.
Three of these haploid nuclei degenerate, leaving only one functional micronucleus in each cell.
The remaining micronucleus divides mitotically to form a migratory nucleus and a stationary nucleus.
The two mates exchange their migratory nuclei, which then fuse with the stationary nuclei inside each cell.
The cells separate as ex-conjugants and later reproduce asexually by repeated binary fission.
Therefore, the true statement is D: each micronucleus divides twice.
Answer:D. Each micronucleus divides twice.