Chapter 17, Problem 1MCQ

Following gastrulation, the cells that have folded inward develop into

a.	endoderm.
b.	ectoderm.
c.	mesoderm.
d.	All of these are correct.

Summary Introduction

Introduction:

Gastrulation is the process of embryonic development in which the blastula develops into gastrula. Gastrula is a cup shaped structure which consists of 3 tissue layers. The germ layer of gastrula gives rise to all of the body’s tissues and organs.

Answer to Problem 1MCQ

Correct answer:

Following gastrulation, the cells that have folded inward develop into endoderm. Hence, the correct answer is options a.

Explanation of Solution

Reason for correct answer:

Option a. is given as, “endoderm.”

The gastrula is made of three layers, in which the innermost is the endoderm that becomes the digestive tract and the internal organs. The cells folding inwards develop into endoderm layer of the gastrula. Hence, option a. is correct.

Hence, the option a. is correct

Reason for incorrect answers:

Option b. is given as, “ectoderm.”

Ectoderm is the outer tissue layer of the gastrula which develops into skin and nervous system. The cells that fold inwards do not form ectoderm. Hence, option b. is incorrect.

Option c. is given as, “mesoderm.”

Mesoderm is the tissue layer that forms between the ectoderm and endoderm. This layer gives rise to muscles, bones, circulatory system, and other specialized structures. It does not develop when the cells fold inward. Hence, option c. is incorrect.

Option d. is given as, “all of these are correct.”

The cells that fold inwards only develop into endoderm, not ectoderm or mesoderm. Hence, option d. is incorrect.

Hence, the options b., c., and d. are incorrect.

Conclusion

The cells that have folded inward develop into endoderm following gastrulation. Thus, the correct option is a.