Answer:
to format a cell based on the value in it
Step-by-step explanation:
you would use conditional formatting on a cell when you want to format a cell based on the value in it.
Reason -
Conditional formatting allows you to format a cell based on the value in it. 
For example, if you want to highlight all the cells where the value is less than 30 with a red color, you can do that with conditional formatting. 
- How would you highlight cells with negative values in it? 
You can use conditional formatting.