<em>Obligate anaerobes</em> are microorganisms killed by normal atmospheric concentrations of oxygen. A <em>facultative anaerobe</em> prefers to produce energy in the presence of oxygen but can survive without it. <span>A <em>photoautotroph </em>is an organism that converts light energy into chemical energy. </span><span>Prokaryotes may perform </span>aerobic<span>(oxygen-requiring) or </span>anaerobic<span> (non-oxygen-based) metabolism and some can switch between these modes. Since we're talking about an environment without oxygen and dies when exposed to oxygen, the preferable answer is A.</span>
the answer is B. OBLIGATE anaerobe. it is the only one that is poisoned by oxygen. if you want to see for yourself just type into google (obligate anaerobe) Took the test and got a 100% :)