CBSE Class 10 Answered

Plants produce male germ cell called pollen and female germ cell called egg for sexual reproduction to occur. In human beings, males produce male germ cells called sperm cells and females produce female germ cells called ova for sexual reproduction. During childhood, all the body energy is focused on the physical and mental growth of the child. This includes increase in height, appearance of teeth, speech, etc. There is delayed maturation of reproductive tissues during this phase. A time of rapid growth and body changes begins in the early teens which makes a boy and a girl appear different and behave differently. This time period between childhood and adulthood is called adolescence. After adolescence, the body of males and females undergoes rapid changes and the production of sex hormones begins. As the rate of general body growth begins to slow down, reproductive tissues begin to mature, which marks the onset of puberty.