The zygote passes through several developmental stages till implantation, Describe each stage briefly with suitable diagrams.

The acrosome plays important role in

Fertilisation of an egg cell it means......

$(1)$ End of process of oogenesis

$(2)$ Induces the completion of the second meiotic division

$(3)$ The corpus luteum degenerates

$(4)$ Signals for maintain progesterone level in blood

$(5)$ Formation of zygote

The attachment of the mammalian blastocyst to the uterine wall is

The fertilized egg divides by the process of

Unfertilized egg of human contains or When released from ovary, human egg contains