What is the independent variable (include units)?

An independent variable is the variable in a experiment that you control, it can be measure in all types of units, ml, liters, cups, mm, etc.

Explanation:

The submarine starts at a depth of 100 feet below sea level and then dives at a rate of 50 feet per minute. Here, elevation is dependent on time. But time is not dependent on any factor. So, the independent variable is time in minutes.

Explanation:

  b.

there are isolated pockets of farming, generally around rivers and oases, which are used for irrigation.