Observe the following figures. (a) (b) (c) (d) Identify the stages (a) to (d) in the figure during development of human baby.

The given figures represent different stages that occur during reproduction in the female body. (a) It represents the attaching of an embryo to the uterus for development. (b) It represents the fertilisation of an ovum by the sperm. (c) It represents the formation of an egg by the ovary. This is followed by fertilisation of the egg in the fallopian tube and development of the embryo. (d) It represents the formation of a zygote by the fusion of male and female gametes.

Observe the following figures. (a) (b) (c) (d) Arrange the stages in correct sequence of development.

The given figures represent various stages of sexual reproduction. The fertilization is represented in (b) whereas zygote formation is represented in (d). The figure (c) represents travel of zygote from the oviduct to the uterus and figure (a) represents attaching of an embryo to the walls of the uterus for development. Hence, the correct sequence is (b), (d), (c) and (a).

Observe the following figures. (a) (b) (c) (d) Explain the development that takes place in figure (a).

Figure (a) represents the embedding of the embryo into the uterus. The zygote divides repeatedly to make a ball of cells called embryo. The embryo travels down the oviduct into the uterus and gets embedded into soft and thick lining of uterus called as implantation. It gets nutrition from the mother for development and gradually develops body parts such as head, eyes, hands, legs etc. The embryo during this stage, where all the body parts can be easily identified, is called a foetus. It takes approximately nine months for the foetus to develop, and then the mother gives birth to a baby.