Astudent investigates if extra yeast (this is an animal cell) or extra sugar will produce the most gas when mixed in a warm water and yeast solution. he uses two bottles with ½ cup of warm water. to the first bottle, he adds 2 teaspoons of yeast and 1 teaspoon of sugar and then puts the balloon on top. he adds 2 teaspoons of sugar and 1 teaspoon of yeast to the second one, then puts on the balloon. he waits and records the changes in the size of the balloons as they fill with gas. what did he forget to do and what gas is produced?