The major systems, organs and structures of the body appear during the __________ stage.

A) zygote
B) embryonic
C) fetal
D) natal

Embryonic Stage

The period in prenatal development from the second to the eighth week after fertilization during which significant growth and differentiation of the embryo occurs.

Major Systems

In psychology and neuroscience, this could refer to the primary functional systems of the brain, including sensory, motor, and cognitive systems.