Given below are two statements :
Statement I:The complex formed by a pair of synapses homologous chromosomes is called a bivalent
Statement II: During pachytene,the four chromatids of each of the bivalent chromosomes becomes distinct and clearly appears as tetrads
In the light of the above statements, choose the most appropriate answer from the options given below :

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Both Statement I and statement II are correct.

Both Statement I and statement II are incorrect

Statement I is incorrect but statement II is correct.

Statement I is correct but statement II is incorrect.

answer is C.

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Detailed Solution

During zygotene, chromosome synapsis is accompanied by the formation of complex structure called synaptonemal complex.

The complex formed by a pair of synapsed homologous chromosomes is called a bivalent or a tetrad.

However, these are more clearly visible at the next stage. The first two stages of prophase I are relatively short-lived compared to the next stage that is pachytene.

During this stage, the four chromatids of each bivalent chromosomes becomes distinct and clearly appears as tetrads.

This stage is characterised by the appearance of recombination nodules, the sites at which crossing over occurs between non-sister chromatids of the homologous chromosomes

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