If gross primary productivity is 120 units per day, and the respiration rate is 30 units per day, net primary productivity is _______ units per day.
A) 4
B) 30
C) 90
D) 120
E) 150

Question

Quizplus · Accepted Answer

Net primary productivity (NPP) is the amount of energy that is left over after plants have undergone cellular respiration. NPP = Gross primary productivity - Respiration rate. 
Using the given values, NPP = 120 units/day – 30 units/day = 90 units/day. Therefore, the correct answer is C) 90.

If Gross Primary Productivity Is 120 Units Per Day, and the Respiration