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Plants absorb most of the nutrients they need from the soil. Since plants have been on earth for a long time, why has Earth's soil not run out of these nutrients?
A Plants make new nutrients from solar energy and return them to the soil.
B When plants die, nutrients are broken down by decomposers and returned to the soil.
C Soil nutrients are always replenished by new nutrients falling from space.
D Farmers must add fertilizer to keep all the nutrients from running out.