Efficiency index is:
the absolute growth rate and the measure of the ability of the plant to produce new plant material.
the relative growth rate and the measure of the ability of the plant to produce new plant material.
the relative growth rate and the measure of the ability of the plant to degrade old plant material.
the absolute growth rate and the measure of the ability of the plant to degenerate old plant material.
Efficiency index is the relative growth rate and the measure of the ability of the plant to produce new plant material.