Standing crop means
A. Mass of living matter at first trophic level.
B. The total amount of biomass of an ecosystem in a specific area at a given time.
C. The total amount of only plants in an area at a given time.
D. The total amount of animals in a specific area at a given time.

Hint:- In an ecosystem, organisms occupy a place in the natural surroundings or a community according to their feeding habits and feeding relationship with other organisms. In every ecosystem, there exist food chains and food webs. Natural interconnection of food chains makes a food web. Based on the source of food organisms occupy a specific position in a food chain known as the trophic level.

Complete Answer:-Plants found in a particular area are called flora. Animals found in a particular area are called fauna of that area. The total amount of biomass of an ecosystem in a specific area at a given time is called a standing crop. Organisms are distributed among different trophic levels according to their nutrition. Primary producers like plants belong to the first trophic level. Primary consumers occupy the second trophic level. The amount of energy flowing from lower trophic levels to higher trophic levels will decrease gradually. Only 10 percent of the energy is transferred to each trophic level from a lower trophic level. Every trophic level has a certain mass of living materials at a particular time. This is called a standing crop. The mass of living organisms is called Biomass. Biomass in a unit area is measured to determine the standing crop. The Biomass can be expressed as dry weight or fresh weight. The dry weight of the biomass is the accurate measurement than fresh weight.

The correct answer is the total amount of biomass of an ecosystem in a specific area at a given time, option (B)

Note:- Standing crops varies according to the environment and ecosystems. Standing crop of each trophic level will be different. Some trophic levels in an ecosystem cannot increase unlimitedly as the energy transfer from one trophic level to the next trophic level is only 10 per cent. Therefore the standing crop of trophic levels decreases from lower trophic levels to higher trophic levels.