The diagram below represents the changes in the number of chromosomes during several processes that occur in an animal.
(i) Name the process of cell division occurring atX and Y.
(ii) State two differences in the behaviour of chromosomes between X and Y.
(i) X-Mitosis. Y-Meiosis
(ii) (a) In X, there is no association of homologous chromosomes but in Y, homologous
chromosomes pair up together to form bivalents during prophase-I.
(b) In X, there is no crossing over as there is no formation of chiasmata but in Y, crossing over occurs at the chiasmata whereby some genes are swapped between homologous chromosomes.