Define the following terms fertilization. puberty and implantation?

Fertilization

• Fusion of a male sperm and a female egg.
• Forms a zygote with genes from both parents.
• Starts the development of a new individual.

Implantation

• After a few days, the zygote becomes a blastocyst and reaches the uterus.
• It attaches and embeds in the uterine lining (endometrium).
• This step establishes pregnancy and allows nourishment of the embryo.

Puberty

• The phase when the body becomes sexually mature and secondary sexual traits appear.
• Girls (often ~10–12 years): breast development, menstruation begins, body shape changes.
• Boys (often ~11–13 years): testis enlargement, more testosterone, voice deepens, facial and body hair.
• Includes a growth spurt, body composition changes, and the ability to reproduce.