Question

Which of the following is/are true/false regarding the development of an embryo?
i. An embryo is made up of many cells.
ii. The stage of development in which all the body parts can be identified is called the foetus.
iii. The stage of development in which the cells begin to form groups that develop into different tissues and organs of the body is called the embryo.
iv. The embryo gets nutrition from the uterus.
A. (i), (ii), and (iii) are true; (iv) is false.
B. (i), (ii), (iii) and (iv) are true.
C. (i) and (iv) are true; (ii) and (iii) are false.
D. (i) and (iv) are true; (ii) and (iii) are false.

Answer 1

Hint: An embryo is defined as a diploid or a multicellular structure that is formed as a result of fertilization and the processes occurring afterward. Moreover, zygote, morula, blastula, gastrula, etc., are all the various stages of an embryo and its development.

Complete answer: The first statement given to us is that an embryo is made up of many cells: This statement is absolutely correct. This is because an embryo is defined as a structure that is made up of two to many numbers of cells. Hence, an embryo is either a diploid or a multicellular structure. Therefore, this statement is true.
The second statement given to us is that the stage of development in which all the body parts can be identified is called the foetus: This statement is absolutely correct. A foetus is defined as a developing baby. After the first trimester, the basic structure of a baby is formed. It is then when it is usually called the foetus. Therefore, this statement is true.
The third statement provided to us is that the stage of development in which the cells begin to form groups that develop into different tissues and organs of the body is called the embryo: This statement is absolutely correct. This is because an embryo is defined as a structure that is made up of two to many numbers of cells. Hence, an embryo is either a diploid or a multicellular structure. A zygote is a diploid structure of an embryo. The morula is a sixteen to thirty-two cell structure. The morula develops into blastula and gastrula which forms the primary germinal layers from which the organs start to develop. Therefore, this statement is true.
The fourth statement given to us is that the embryo gets nutrition from the uterus: This statement is not correct. This is because the embryo as well as the foetus derive nutrition from the placenta. The placenta is a functional and structural unit between the developing embryo or foetus and the mother’s body. Hence, the placenta is an organ connecting the foetus with the wall of the uterus or the uterine wall. Therefore, this statement is false. Thus, based on the above information we can conclude that the statements (i), (ii), and (iii) are true, whereas, statement (iv) is false.
Hence, the correct answer is option (A).

Note: The placenta is made up of both the maternal as well as the foetal parts. The mixing of the maternal and the foetal blood occurs in the placenta. The placenta is like an ultrafilter from which the nutrients pass from the mother to the foetus. Moreover, it also acts as an endocrine gland and synthesizes several important hormones.