(i) True regeneration or reparative regeneration occurs when a structure is removed by an external source and the body replaces the lost structure. The liver has the greatest regenerative capacity of any organ in the body.
(ii) Before fertilizing the ovum, the sperm prepares itself for the act of fertilization and undergoes many changes. These changes in a sperm just prior to fertilization are called capacitation.
(iii) It is the onset of menstruation in a young female at the age of about 12 to 13 years.
