Assertion Holoblastic cleavage with almost equal-sized blastomeres is a characteristic of placental animals. Reason Eggs of most mammals, including humans are of centrolecithal type.

Question

Assertion Holoblastic cleavage with almost equal-sized blastomeres is a characteristic of placental animals. Reason Eggs of most mammals, including humans are of centrolecithal type. (A) extinction of these species from other regions (B) continental separation (C) absence of terrestrial route to these places (D) retrogressive evolution

Tardigrade Admin · Accepted Answer

Eggs containing a small amount of yolk or without any yolk are known as micro-lecithal/ alecithal/oligolecithal/meiolecithal eggs. Such eggs are found in starfish, Amphioxus, Eutherian mammals including rabbit and human beings. In such egg, equal holoblastic cleavage takes plae in which equal or approximately equal-sized blastomeres are produced.

Q. Assertion Holoblastic cleavage with almost equal-sized blastomeres is a characteristic of placental animals. Reason Eggs of most mammals, including humans are of centrolecithal type.

extinction of these species from other regions

continental separation

absence of terrestrial route to these places

retrogressive evolution

Q. Assertion Holoblastic cleavage with almost equal-sized blastomeres is a characteristic of placental animals.
Reason Eggs of most mammals, including humans are of centrolecithal type.