Biology · Reproduction in Animals

Read the following paragraph and choose the option with the set of words which would fill the blanks correctly in the given order. During fertilisation, the sperm cell from the father and the egg cell of the mother fuse to form a W which divides repeatedly to give rise to a ball of cells. The cells begin to develop into different organs a nd tissues. This developing structure called X gets embedded in the wall of Y. The stage of X in which all body parts can be identified is called Z. W, X, Y, Z respectively are: