A biologist examines a single-celled organism isolated from a hot spring. The organism is a photosynthetic halophile that uses the pigment bacteriorhodopsin. In which kingdom should the biologist classify the organism? A.
Protista
B.
Bacteria
C.
Fungi
D.
Archaea

D. Archaea

Explanation:

The pigment bacteriorhodopsin  is found in Archaea. Bacteriorhodopsin is an integral membrane protein and acts a proton pump.It uses light energy to move protons from inside of the cell to outside across membrane.The proton gradient generated by the movement of protons is converted into chemical energy.

Archaeans include organisms that live in extreme environments such as hotsprings ,hypersaline water, thermal vents.

Bacteriorhodopsin is present in Halobacterium(a group of Archaea that can live in extremely saline water).

im not sure about this one

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