Q.Define population and community.

The only correctly ascending sequence given is Community -> Ecosystem -> Landscape -> Biome.

Ecologists organise living systems into a nested hierarchy of increasing scale and complexity: an individual organism belongs to a population (all individuals of one species in an area), populations of different species interacting in an area form a community, a community together with its physical (abiotic) environment constitutes an ecosystem, a mosaic of interacting ecosystems across a geographic area forms a landscape, and landscapes with broadly similar climate and vegetation type are grouped into a biome, with all the biomes of Earth together making up the biosphere. Checking each option against this true order: "Community -> Ecosystem -> Landscape -> Biome" places each level correctly above the previous one (Community < Ecosystem < Landscape < Biome) and is therefore correct; "Individual Organism -> Population -> Landscape -> Ecosystem" wrongly places Landscape before Ecosystem, when Ecosystem is actually the smaller, low …