When researchers are measuring plant productivity, they usually harvest and measure above-ground biomass. But with grassland plants, it is common to find that most of an individual's biomass is in its root system. Why don't researchers measure below-ground biomass as well?

Because of the fibrous root network of grasses.

Explanation:

Measuring below ground biomass of grass plants is technically impossible and difficult because of the fibrous root network different plants form with one another and within the soil. The network virtually makes it impossible to individually extract all the underground biomass of each grass.

there are mainly three domains in biological classification namely; archaea, bacteria, and eukarya.

archaea includes all the prokaryotic cells which are characterized by their lipid membranes. they have branched hydrocarbon which is attached to glycerol through an ether linkage.

bacteria includes all the prokaryotic cells, the cell membrane of which are made up of the unbranched fatty acid chain. in addition, they are attached to glycerol through an ester bond.

eukarya includes all the eukaryotic cells, that is, the cells contain a nucleus and other membrane-bound cell organelles.

they can be autotrophic as well as heterotrophic, unicellular as well as multicellular

they include kingdoms like protista, plantae, animalia, fungi et cetera.

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explanation: