Answer:
C. Different heights of holes in the container
Explanation:
The independent variable is the variable that changes. So the independent variable is C because the heights of the holes change.
Answer:
= 
Explanation:
Tollens test is carried out to perceive difference between aldehydes and ketones on the basis of their capability to oxidized easily.
when Tollens react with aldehyde (heptanal) , a silver mirror is form on inner side of container.
The reaction between tollens and heptanal is given as
= 
The chemical change that involves breaking down substances using electricity is C. Electrolysis.