Biology Class Exam

Students in an advanced Biology class were taking their exam.

The last question was, 'Name seven advantages of Mother's Milk', worth
70 points or none at all.

One student, in particular, was hard put to think of seven advantages.
He wrote:

(1) It is 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 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 the cat can't get it.

He got an A.