Question

In a human foetus the limbs and digits develop after
A. First trimester
B. 8 weeks
D. 12 weeks
d. ${5^{TH}}$ month

Answer 1

The fertilization is the beginning of human development as the man sperm combines to the egg in the uterine tube of the woman furthering the implantation process.

Step by step answer: In the first week after fertilization, the embryo continues to grow, in the fourth week the embryo develops into a head and a trunk, the brain develops and the eyes and ears begin to form and the heart continues to develop as it beats regularly. The foetus in humans, where limbs are initially undifferentiated mesoderm and are covered with the epithelium. The limb bud primordia appear in small elevation at the end of the fourth month, in the sixth week of the pregnancy most of the development in the limbs can be seen but are not differentiated, at the ${8^{TH}}$ week of the gestation the development can be seen clearly where feet and hands can be distinguished, but still, it appears little webbed, some weeks later the limbs and digits can be identified clearly. In the human foetus the limbs and digits develop by the end of the second month of the pregnancy.
Hence, the correct option is ‘B’.

Note: The zygote in humans gets cleaved very rapidly and forms a ball of the cell which then undergoes gastrulation and forms three-germ layer, which is further subjected to organogenesis, development of the organs and after 8 weeks of the pregnancy limbs and digit development can be .