[c9-adams]

I am currently learning about activity diagrams for my exam tomorrow. I am stuck on one particular question:

In terms of activity diagrams, when cooking food in a microwave, the cold food is:
an output
a control input
an input
an activity

If anyone could help me on this it would be greatly appreciated!

Thankyou.

[mojo666]

Setting aside computer science, how would you describe cold food in the microwaving process? People don't often pick arbitrary words to describe things. They are usually based on some kind of analogy.