Question

The shortest gestation period among the following is seen in
A.Man
B.Elephant
C.Cat
D.Mouse

Answer 1

Hint: Parturition is the birth of a fully grown baby from the womb of the mother. Parturition occurs in three steps. Gestation or incubation period in humans is approximately 9 months.

Complete answer:Parturition is the ousting of the full-fledged young one from the mother's uterus after the incubation time frame. The period between fertilization and parturition is called gestation. The normal span of human pregnancy is 9 months.
Incredible contraction of the uterus toward the finish of pregnancy causes removal/expulsion of the baby. Parturition is induced by a complex neuroendocrine mechanism involving cortisol, estrogens, and oxytocin.
Signals for parturition originate from the fully formed fetus and placenta including mild uterine contractions called fetal ejection reflex.
Labour can be divided into three stages-
1. Stage of dilation: During this stage regular uterine contraction rupture the amniotic sac and complete dilation of the cervix occur. Amniotic fluid starts flowing through the vagina which pushes the fetus towards the cervix.
2. Stage of expulsion: Baby passes through cervix and vagina and is delivered.
3. Placental stage: After delivery placenta or after birth is expelled by powerful uterine contractions.
The mouse has a gestation period of 20 days, the cat has a gestation period of 63 days and the elephant has a gestation period of 624 days.
So, the correct answer is option D. Mouse.

Note:Oxytocin also is known as the birth hormone, release is triggered by mild uterine contractions. It causes powerful contractions of myometrium which in turn cause further secretion of oxytocin. Stimulatory reflex between uterine contraction and oxytocin secretion resulting in stronger and stronger contractions leading to the expulsion of the fetus.