Question

In a human foetus the limbs and digits develop after
A. 8 weeks
B. Fifth month
C. First trimester
D. 12 weeks.

Answer 1

The development of the human embryo follows fertilization, and continues as fetal development. By the end of the tenth week of gestational age the embryo is called a fetus.

Complete answer:
A fetus is characterized by the presence of all the major body organs, though they will not yet be fully developed and functional and some not yet situated in their final anatomical location.
(A):- 8 weeks - In human prenatal development, fetal development begins from the ninth week after fertilisation and continues until birth. Yes, in a human foetus the limbs and digits develop after 8 weeks.
So, "A" is the correct answer.

(B):- Fifth month -The development at this stage of foetus are eyebrows and eyelids are now in place. Foetus is developing muscles and exercising them. Hair begins to grow on a baby's head. The foetus shoulders, back and temples are covered by a soft fine hair called lanugo. This hair protects foetus and is usually shed at the end of the baby's first week of life. By the end of the fifth month, the baby is about 10 inches long. So, "B" is not the correct answer.

(C):- First trimester - The first trimester will span from conception to 12 weeks. This is generally the first three months of pregnancy. During this trimester, the embryo will change from a small grouping of cells to a fetus that is starting to have a baby’s features. By the end of the third month, the foetus is fully formed. All the organs and limbs (extremities) are present and will continue to develop in order to become functional. The baby’s circulatory and urinary systems are also working and the liver produces bile. But the part of trimester, the eighth week, after completion of which limbs and digits develop. So "C" is not the correct answer.

(D):- 12 weeks - 12 weeks completion of foetus can also be said as the first trimester is completed. Up till this period the foetus is fully formed. All the organs and limbs (extremities) are present and will continue to develop in order to become functional. The baby’s circulatory and urinary systems are also working and the liver produces bile. And the foetus is about 4 inches long. So "D" is not the correct answer.

Hence, the correct answer is option (A).

Note: Embryonic development in the human, covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a fetus. The germinal stage refers to the time from fertilization through the development of the early embryo until implantation is completed in the uterus. The fetus has more recognizable external features and a more complete set of developing organs.