Concept explainers
Following gastrulation, the cells that have folded inward develop into
- a. endoderm.
- b. mesoderm.
- c. ectoderm.
- d. All of the above are correct.
Introduction:
Gastrulation is a period in the development of an embryo of animals, in which a single layered blastula folds itself in such a way that it forms a cup shaped structure called gastrula. Gastrula further contains two or three layers of tissue. It includes the endoderm, ectoderm and mesoderm.
Answer to Problem 1MCQ
Correct answer:
The cells that have folded inward develop into endoderm, after gone through the gastrulation phase. Therefore, option (a) is correct.
Explanation of Solution
Reason for the correct statement:
The blastula rearranges itself to develop the gastrula, following gastrulation the cells that fold inward develop into the endoderm. Endoderm is the inner most layer which contributes to the development of an embryo
Option (a) is given as “endoderm”.
As, “endoderm is the inner most layer which is formed by the folding of cells after gastrulation phase. Endoderm is the primary germ layer which contributes to the development of an embryo in early stage”, it is the right answer.
Hence, option (a) is correct.
Reasons for the incorrect statements:
Option (b), is given as “mesoderm”.
Mesoderm is the middle layer formed between ectoderm and endoderm. This is the third primary germ layer which also contributes to the development of an embryo. Mesoderm is formed by the interaction of two germ layers including ectoderm and endoderm. Hence, it is a wrong answer.
Option (c), is given as “ectoderm”.
Ectoderm is the outermost germ layer that also forms during the development of an embryo. It covers the outside of the embryo. Hence, it is a wrong answer.
Option (d), is given as “all of the above are correct”.
Endoderm, ectoderm and mesoderm all are the primary germ layers which are formed during the development of an embryo. Ectoderm is the outer layer of tissue and mesoderm is the inner layer of tissue. The cells that have folded inward result in the formation of endoderm. Hence, it is a wrong answer.
Hence, options (b), (c), and (d) are incorrect.
Endoderm is formed by the inward folding of cells followed after gastrulation. Endoderm is the primary germ layer which contributes to the development of an embryo in the early stage.
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