C) The amount of living matter in a component population of an ecosystem at any time
D) All the crop plants in an area
Explanation
A certain mass of living material at each trophic level of an ecosystem at a particular time is called standing crop. The standing crop is measured as the mass of living organisms (biomass) or the number in a unit area.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.