Cyanobacteria which is a type of algae. It conducts photosynthesis and without it there may not have been life today because they didn't need oxygen to survive and in order to have oxygen there had to have been some form of life...
<span><span><span>The experimental method is usually taken to be the most scientific of all methods, the 'method of choice'.</span><span> </span><span> </span><span>The main problem with all the non-experimental methods is lack of control over the situation.</span><span> </span><span>The experimental method is a means of trying to overcome this problem.</span><span> </span><span> </span><span>The experiment is sometimes described as the cornerstone of psychology</span>
</span></span>
The 3 domains of life would be, Archaea, Bacteria and Eukarya!
I think the answer is p wave on the penn foster test