Mother"s milk

Students in Advanced Biology class were taking their mid-term exam. The last question was," Name seven advantages of Mother's MILK." One student, in particular was hard put to think of seven advantages. However , he wrote:
1. It's the perfect formula for the child
2. It provides immunity against several diseases.
3. It is always the right temperature
4. It is inexpensive.
5.It bonds the child to the mother and vice versa
6.It is always available as needed.
And then the student was stuck. Finally, in desperation, just before the bell rang indicating the end of the test, he wrote:
7. It comes in two attractive containers and it's high enough off the ground that the cat can't get it.
He got an "A"