Hey there! I'm happy to help!
A. Predictions are guesses you make about the result of a trial. Let's say that you want to test what will happen if you put less eggs into a cookie recipe. You could make a prediction that the cookies will be more crumbly. This is not the term for things that are the same between two groups, so this is incorrect.
B. Controls are a type of variable that isn't influenced in a unique way as part of the experiment. This is to be able to compare the things you change to a thing that hasn't changed. With our cookie example, a control group would just be a cookie recipe with the normal amount of eggs. Then we can compare a normal cookie to one with less eggs. We see that a control is a type of group, and not a specific thing that is similar or different between the groups, so this is incorrect.
D. Variables are things that can change or vary in your experiment. There are independent variables, which are things that you change, such as the number of eggs in the recipe. Then, you have dependent variables such as color, texture, taste, etc. However, these can change depending on the group because the number of eggs could switch, so this is the wrong term and incorrect.
C. Constants are things that you do not change as part of your experiment. You do not change these variables. In our case, the constants will be all of the other ingredients like the amount of flour, milk, water, sugar, etc. If we have a control group and a group with less eggs, these things will remain constant in both of them. So these things are the same between the two groups, so this answer is correct.
We call the things that are the same between the two groups C. constants.
Have a wonderful day and keep on learning! :D
