Mass of living matter at a trophic level in an area at any time is called
Standing crop
deteritus
humus
standing state
The entire amount of living matter in a population at any particular time is referred to as a standing crop and is expressed as biomass (permanent biomass) or its energy equivalent.
Throughout the year, permanent crops could alter.
For instance, the variation in deciduous tree populations from summer to winter.
The final answer is The mass of living material at a trophic level at a particular time is called standing crop.