Answer:
10 V
Explanation:
The potential difference between two points is the amount of work required to carry a unit charge from one point to the other point. This would result in a potential difference between this two points.
The difference between the potential across two points B and A is 
From the image attached:

Efficiency is completing a task as fast a possible the the least amount of effort.
It is D, you can not replace minerals. This makes them valuable.
Blood cell : Eukaryotic cell
and
Bacteria : Prokaryotic cell.