Chapter 24, Problem 17A

Summary Introduction

Introduction:

A layer is formed at the earliest stages of embryo development it is known as Germ Layer. It comprises of three layers : Ectoderm, mesoderm and endoderm. These layers will help in developing every organs and tissues all together.

Answer to Problem 17A

Correct answer:

The correct answer is option ( A) The cells are directly aligned.

Explanation of Solution

Explanation/justification for the correct answer:

Option ( A) The cells are directly aligned.

The location of mesoderm indicates the alignment of ectoderm, endoderm. Mesoderm is the middle layer which makes sure that all the cells are aligned together.. So,this answer is correct.

Explanation for incorrect answer:

Option (B) the outcome of each cell can be changed

The outcome of the cell can be changed which can lead to the variation of animals. .So, this is an incorrect answer.

Option (C)the mouth develops from the gastrula opening.

The mesoderm is formed from the cells that breakaway from endoderm, which is near the opening of gastrula.So, this is an incorrect answer.

Option (D) The coelom forms from pouches of mesoderm

In highly evolved animals,a mesoderm is formed between ectoderm and endoderm in a developing embryo, where the coelom comes up from the pouches that grow and separates from the digestive tract.So, this is an incorrect answer.

Conclusion

The location of mesoderm indicates that the cell are directly aligned. Hence, the correct answer is option (A) genes.