Cleavage and Blastulation
This is the inherent nature of the sexually reproductive multi-cellular animals that their body originates from a large-sized, single celled (unicellular), nutrient-filled, diploid and fertilized egg or zygote. In them, immediately after the activation of egg either through the intervention of a spermatozoon (fertilization) or through some parthenogenetic agent (parthenogensis), the activated egg is passed [...]
