CBSE Class 9 Answered
The events during the birth process are probably triggered by changes in the level of hormones in the mother's body.
Labour is brought about by the repeated contractions of the uterine muscles, which increase in strength and frequency as the baby is pushed out of the uterus, through the cervix and down the vagina. As this starts, a bag of liquid called the amnion breaks. Througout the birth, the baby continues to be attached via the umbilical cord and palcenta to the mother's body systems. When born, the baby can breathe air, once its lungs have been cleared of fluid, and the umbilical cord is then clamped and cut. A short time later, the placenta is also expelled from the uterus, as the after-birth.