Describe the following: (a) synapsis (b) bivalent (c) chiasmata
Draw a diagram to illustrate your answer.

Explanation

(a) Synapsis
The pairing of homologous chromosomes is called synapsis. This occurs during the second stage of prophase I or zygotene.
ltimg src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/NCERT_BIO_XI_C10_E01_007_S01.png" width="80%"gt
(b) Bivalent
Bivalent or tetrad is a pair of synapsed homologous chromosomes. They are formed during the zygotene stage of prophase I of meiosis.
ltimg src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/NCERT_BIO_XI_C10_E01_007_S02.png" width="80%"gt
(c) Chiasmata
Chiasmata is the site where two sister chromatids have crossed over. It represents the site of cross-over. It is formed during the diplotene stage of prophase I of meiosis.
ltimg src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/NCERT_BIO_XI_C10_E01_007_S03.png" width="80%"gt