Define bacteria, archaea and eukarya

Archaea- is the bunicellular microorganisms that is genetically distinct from bacteria andeukaryote & often inhabiting extreme environmental conditions
Eukarya -the domain comprised of eukaryotes or organisms whose cells contain a truenucleus.
Bacteria- a member of a large group of unicellular microorganisms that have cell walls but lack organelles and an organized nucleus, including some that can cause disease