Eco System

The correct option is(B): Grain size, soil composition and aggregation.

The option that determines percolation and water holding capacity of soils is "Grain size, soil composition, and aggregation." These factors affect the pore spaces within the soil, which in turn influence the movement of water through the soil and its ability to retain water. Climate, weathering process, and soil development also play important roles in soil characteristics, but they may not directly determine percolation and water holding capacity.

The correct statement is: (A) Certain mass of living material at each trophic level is called as standing crop.

Therefore, the correct option is: (A) and (E) only.

The vertical distribution of different species occupying different levels is called "Stratification."

Stratification refers to the division of a habitat or ecosystem into distinct vertical layers or zones, with each layer occupied by specific species or groups of organisms. This vertical arrangement allows different species to occupy different niches or ecological roles within the ecosystem, utilizing different resources and adapting to specific environmental conditions at various levels.