Question

what are the changes seen in a girl and a boy at the time of puberty

Answer 1

Puberty differs in a number of ways between boys and girls. Girls start puberty about 1 to 2 years earlier than boys, and they generally finish more quickly.
Girls reach adult height and are able to have children approximately 4 years after the first physical signs of puberty, but boys continue to grow for about 6 years after the first visible signs.