Question

Which among the following is incorrect about arrangement of cells in embryo?

(a) The word “blasted” derives its origin from the word blastula which means a hollow ball of cells formed during the early stage of embryo

(b) If the number of cell layers in blastula is two in number, i.e. ectoderm and endoderm, then such organisms are considered to diploblastic

(c) If the number of cell layers in blastula is three in number, i.e. ectoderm, mesoderm and endoderm, then such organisms are considered to triploblastic

(d) In diploblastic organisms, mesoglea, a well differentiated substance, is present between endoderm and ectoderm

This question was posed to me in an online interview.

I want to ask this question from Basis of Classification in Animals topic in division Animal Kingdom of Biology – Class 11

Answer 1

Correct answer is (d) In diploblastic organisms, mesoglea, a well differentiated substance, is present between endoderm and ectoderm

For explanation: The word “blasted” derives its origin from the word blastula which means a hollow ball of cells formed during the early stage of embryo. If the number of cell layers in blastula is two in number, i.e. ectoderm and endoderm, then such organisms are considered to diploblastic. If the number of cell layers in blastula is three in number, i.e. ectoderm, mesoderm and endoderm, then such organisms are considered to triploblastic. In diploblastic organisms, mesoglea, an undifferentiated substance, is present between endoderm and ectoderm.