This document provides information about reproduction in organisms and humans. It discusses that reproduction allows organisms to produce new individuals of the same species for survival and population growth. During reproduction, DNA is copied but not identically, allowing for slight variations between offspring. This variation is important for adaptation to environmental changes and evolution. There are two main types of reproduction: asexual, which involves a single parent, and sexual, which involves two individuals. In humans, fertilization occurs when a sperm fuses with an egg in the female's fallopian tubes or uterus. The zygote then implants in the uterus and develops into an embryo over nine months until birth.