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Cleavage in mammals :
A
Holoblastic equal
B
Holoblastic unequal
C
Superficial
D
Discoidal
Detailed Solution
The mammalian (human) egg is alecithal (has very little yolk), so the cleavage furrows divide the whole egg completely. This is holoblastic cleavage.
The blastomeres formed are nearly equal in size, so it is described as holoblastic and nearly equal (in detail, slightly unequal and rotational).
Discoidal cleavage occurs in the yolky eggs of birds and reptiles, and superficial cleavage in insects.
So, as per the answer key, cleavage in mammals is holoblastic equal.
The blastomeres formed are nearly equal in size, so it is described as holoblastic and nearly equal (in detail, slightly unequal and rotational).
Discoidal cleavage occurs in the yolky eggs of birds and reptiles, and superficial cleavage in insects.
So, as per the answer key, cleavage in mammals is holoblastic equal.