Answer:
The correct answer is - fetal stage.
Explanation:
The fetal stage initiates at the ninth week of fertilization and lasts up to the thirty-eighth week of fertilization. It is the approximately 30 week-long stage that involves a rapid change where the fetus change from 3 centimeters in length and around 3 grams in weight to its 20 times in size.
It is the most important and critical stage for the unborn as many important changes take place in this stage which continues until birth.
Thus, the correct answer is- the fetal stage.
