A segment of DNA molecule comprises of 546 nucleotides. How many cytosine nucleotides would be present in it if the number of adenine nucleotides is 96?

Mosses and frogs both need water as a medium for fertilisation. Where does syngamy occur and how is it ensured in both these organisms?

OR

Write the basis of categorising animals as oviparous or viviparous, giving one example of each.

(a) You are given castor and bean seeds. Which one of the two would you select to observe the endosperm?

(b) The development of endosperm precedes that of embryo in plants. Justify.

How is ‘somatic hybridization’ carried out? Mention one example of a somatic hybrid.

How are DNA fragments visualised during gel-electrophoresis? What is elution?