Answer :
Unicellular organism can
also be refers to as single-celled organism and they are made up of one cell compared
to multicellular organism that have more than one cell. These organisms fall
into two groups: prokaryotic organisms (bacteria and archaea) and Eukaryotic organisms (unicellular fungi, protozoa, unicellular algae).
Thus, unicellular organism can live in hot or cold environment and these characteristic give hopes to scientist that these organisms can be found in any other planets.