Across nearly seven million years, the human brain has tripled in size. The most likely the reason for the evolution of a larger brain in humans is that a larger brain allows humans to solve complex problems. Large, complex brains enable humans to process and store a lot of information and to interact with each other and with their surroundings better. The brain we now humans have is the largest and most complex of any living primate.
b. marsupials.
c. placentals.
d. bird-like.
b. fertilization.
c. gastrulation.
d. cleavage.
e. growth.
The answer is (b.) fertilization
The fertilization is the stage where the egg cell or the so-called ovum fused with the sperm cell which eventually leads the development of the embryo or the zygote. The Embryogenesis starts when the zygote undergoes mitotic divisions or also known cleavage process.