What is the definition of an umbilical cord?
A)a mammal which gives birth to a fetus that moves into a pouch for protection and nourishment
B)a mammal that has just one passage for elimination and egg laying
C)having a placenta, the organ that nourishes young until birth
D)a tube that connects an unborn baby to its mother for nourishment
E)the gland of a mammal that produces milk for the young