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