Answer:
The period during which the major organs and structures of the organism first develop.
Step-by-step explanation:
Germinal stage:
Germinal stage term is used for first two weeks of gestation after conception.
Embryonic period:
Embryonic period is considered from third week to the eighth week after conception.
Fetal period:
From ninth week until birth stage is known as fetal period.
Now, the embryonic period of gestation starts after germinal stage and during this phase the major organs and structures are formed within the growing mammal.