How is the Sex of the Baby Determined?
Sex chromosomes play a crucial role in determining the sex of the unborn baby. Typically, females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). The father’s sperm carries either an X or a Y chromosome, while the mother’s egg always contributes an X chromosome. If the sperm carrying an X chromosome fertilizes the egg, the resulting combination (XX) will develop into a female baby. On the other hand, if the sperm carrying a Y chromosome fertilizes the egg, the combination (XY) will develop into a male baby.
Also Read: Sex Determination
NCERT Notes Science for Class 8 Chapter – 7: Reaching The Age of Adolescence
NCERT Notes for Class 8 Science Chapter – 7: Reaching The Age of Adolescence: Growing up is a natural process. Growth begins from the day one is born. But upon crossing the age of 10 or 11, there is a sudden spurt in growth which becomes noticeable. The changes taking place in the body are part of growing up. They indicate that the individual is no longer a child but is on the way to becoming an adult. The period of life, when the body undergoes changes, leading to reproductive maturity, is called Adolescence.
NCERT Notes on Reaching The Age of Adolescence of Class 8 Science Chapter – 7: Adolescence begins around the age of 11 and lasts up to 18 or 19 years of age. Since this period covers the ‘teens’- 13 to 18 or 19 years of age, adolescents are also called ‘teenagers’. In girls, adolescence may begin a year or two earlier than in boys. Also, the period of adolescence varies from person to person. The human body undergoes several changes during adolescence. These changes mark the onset of Puberty. Puberty ends when an adolescent reaches reproductive maturity.