Based on the pyramid, which organism(s) provide the most available energy?
a)
predator fish
b)
birds and mammals
c)
insects and zooplankton
d)
phytoplankton and bacteria

The correct answer is option D) phytoplankton and bacteria.

It is because of the fact that with advancement in trophic levels in a food chain or food web, energy is lost by 10%. So, the organism which is at lowest position in a food chain will have the most energy while the one at the top will have the least energy. It means that a primary consumer who feeds on plants will have 10% less energy than plants & a secondary consumer who feeds on a primary consumer will have 10% less energy than the primary one. Plants are at the base position in a food chain and phytoplanktons are microscopic algae which are considered as plants. So phytoplanktons will lie at the base position in a trophic level and they will have most available energy. So the correct answer is option D.

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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