The fetal stage occurs from week nine to the end of pregnancy. What is this stage primarily known for?

The fetal stage, which spans from week nine until the end of pregnancy, is primarily characterized by a period of growth. This stage is essential as it involves significant physical development—increased size, weight gain, and maturation of the body's systems.

During this time, the fetus grows rapidly in size and matures enough to survive outside the womb. The complexity of the body becomes more pronounced, with further development of tissues and organs that were initiated in earlier stages.

While cell division, organ development, and the formation of the placenta are critical processes that occur at different stages of pregnancy, the fetal stage is specifically focused on the growth and maturation of the already formed structures rather than their initial formation or division. Thus, the defining characteristic of this stage is the extensive growth of the fetus, which prepares it for life after birth.