Random fertilization allows random combination of genetic information, which helps synthesize genetically unique gametes. The fusion of a unique sperm together with a unique egg can introduce further variation.
Following gastrulation, the next major development in the embryo is neurulation, which occurs during weeks three and four after fertilization. This is a process in which the embryo develops structures that will eventually become the nervous system
A. Extinction is a natural part of life on earth
Pull Of Gravity , that is why you have weight or else without gravitational pull you only have mass hence the equation w = mg
