(a) Which is the simplest domain?
Bacteria is the simplest domain because its organisms are unicellular prokaryotes with no nucleus and simple cell structures.
(b) Which is the complex domain?
Eukarya is the most complex domain because it includes multicellular organisms with complex organelles and well-defined nuclei.
(c) Are most bacteria harmful?
No, most bacteria are harmless or beneficial. They play vital roles in decomposition, digestion, and nitrogen fixation, while only a small percentage are pathogenic.
(d) Which domain(s) can flourish or survive in most adverse conditions?
Archaea can survive in extreme conditions like high temperatures, acidic environments, and deep-sea hydrothermal vents due to their unique cell membrane composition and enzymes.