Science Experiment 1 - What does yeast need to be active?

We wanted to see what yeast needed in order for it to be active.  We put different things in each jar and watched to see what happened.  In the first jar we put cold water and salt, in the second jar is cold water and sugar, in the third jar is warm water, in the fourth jar is warm water and salt, in the fifth jar there is warm water and sugar.  We put a teaspoon of yeast in every jar and this is the result.

We learnt that yeast needs sugar and warm water or cold water to be active.  But it worked best with warm water.