A belly button or tummy button is technically known as a navel or umbilicus. Humans are part of the group of animals called mammals, and other mammal babies develop inside their mother in the same way, getting nourishment from the placenta via an umbilical cord. Animals that develop in eggs, rather than in a womb, still need food. But, instead of getting this from the mother, the food is present in the egg in a special area known as the yolk sac.
Read more…
Our Score
Click to rate this post!
[Total: 1 Average: 5]
