In a set of classic experiments performed in the early 1950s, Urey and Miller subjected an experimental system composed of H2, CH4 (methane), and NH3 (ammonia) to electrical sparks. A few days later, they found _________ in their system.
What kind of molecule is thought to be the most likely to have been the first genetic material?
According to the biological species concept, species are natural populations of organisms that have the potential to interbreed and are ________ isolated from other such populations.
The classification rank that includes genera but not orders is: