The development of a fetus after conception occurs in three distinct stages: 1. The Germinal Stage: This is the first stage that occurs from conception to about two weeks. During this time, the fertilized egg (zygote) undergoes rapid cell division and eventually implants itself into the uterine wall. 2. The Embryonic Stage: This stage lasts from the third week to the eighth week of pregnancy. During this period, the major organs and body systems begin to form, including the heart, brain, and spinal cord. This is a critical time for development, as the embryo is particularly vulnerable to environmental factors. 3. The Fetal Stage: This stage begins at the ninth week and continues until birth. During the fetal stage, the fetus grows significantly in size and weight, and the organs and systems continue to mature and become functional. This stage is characterized by the development of features such as limbs, facial structures, and the ability to move.