Class 12 NEET Biology Human Reproduction Questions Part 1

(a) : The anount of yolk and how it is distributed determines the type of eleavage. On this basis cleavage is of two types:
(i) Holoblastic (total cleavage) - where the segmentation line passes through the entire egg. It occurs in alecithal (without yolk), microlecithal (with very little amount of yolk) and mesolecithal (little amount of yolk) egg.
(ii) Meroblastic (partial cleavage) - where segmentation line does not pass through the egg and remained confined to a part of the egg. It occurs in megalecithal (large amount of yolk) egg.