Question

Observe the following figures.

(a)	(b)	(c)	(d)

1. Identify the stages (a) to (d) in figure during development of human baby.
2. Arrange the stages in correct sequence of development.
3. Explain the development that takes place in any one stage.

Answer 1

1. The figures showing stages during development of embryo are identified as - 
   (a) Embedding of the embryo in the uterus (implantation).
   (b) Fertilisation (fusion of egg and sperm).
   (c) Stages in development of an embryo from the zygote in the oviduct, till it gets embedded in uterus.
   (d) Zygote (showing fusion of nuclei)
2. The above stages in sequence are :
   (b) Fertilisation → (d) Zygote formation → (c) Development of embryo → (a) Implantation of embryo in uteras.
3. Development of embryo The embryo after being implanted in uterus, continues to develop and divide and differentiate into body parts. The stage of embryo when body parts become distinct and identified is called foetus. After complete development of foetus, mother gives birth to baby.