Actually, it could indeed be the independent variable.
Answer:
A scientific problem is something you don't understand but you can do an experiment to help you understand. Scientific problems are usually based on observation of scientific phenomena. Here is some advice to help you identify a scientific problem you can address by designing your own experiment.
Explanation:
Example of a scientific problem are Clean Drinking Water.
Answer:
I think its D. and A hopefully that's right
It is greater than the total mass of the products