In which of the following animals is a dimorphic nucleus found?

Explanation

Dimorphic nucleus means that two types of nuclei are present in P. caudatum - a large macronucleus and a small micronucleus. The macronucleus is roughly kidney shaped with an inconspicuous nuclear membrane. The macronucleus is the somatic or vegetative nucleus that controls the day to day metabolic activities of the cell. The micronucleus is lodged in a depression on the surface of the macronucleus. It is usually spherical, with a nuclear membrane and with diploid number of chromosomes. It controls the reproductive activities of the organism. Amoeba, Trypanosoma and Plasmodium have only one nucleus.