Question

Gestation period of 280 days is calculated from the day of
A. Last menstruation
B. Fertilization
C. Next Menstruation
D. Puberty

Answer 1

Hint: Gestation period is the time duration between the fertilization of the egg and the delivery of a fully grown baby. The development of the fetus takes place inside the female individual in all viviparous animals. Once the fertilization takes place the menstruation stops.

Complete answer:
To know the correct answer to the question, we must be well aware of the gestation period in humans.
 The male sperm fertilizes the ovum and the zygote is formed which is implanted in the uterus. Now, the menstruation stops till the time the fetus develops and the fetus is expelled out of the body of the female. The time duration between the development of the fetus and its delivery to the outside world is known as the gestation period.
To be more precise, we can say that it is the time between the last menstruation and the expected delivery date when the fully grown baby is delivered.

Therefore, the correct answer to the question is option A, i.e last menstruation.

Note: The gestation period is different in different animals. For humans it is 40 weeks or 280 days. We all know that the menstruation temporarily gets stopped because now the implantation has taken place and the blood is now nourishing the fetus and also the amnion which further protects the fetus.