All organisms in the kingdom must be viewed using a microscope

Archaebacteria

Explanation:

All organisms in the archaeobacterial kingdom can be viewed with the aid of a microscope, which is able to enlarge images hundreds or thousands of times. However, without the microscope it is possible to see the colonies, structures formed by thousands of them.

Most members of this realm are chemosynthetic autotrophic while bacteria. This feature allows them to live in extreme places where many other organisms would not survive. Usually these organisms have characteristics that not only allow them to survive in these environments, but also seem to improve in extreme environments.

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:

it's c. (to reduce the greenhouse effect/carbon gasses)