What is the main evidence for why the physical and ecological environment of the early Earth is thought to have been very hostile? Comparative embryological studies that show homologies in structure
Experimental results of similar conditions of early Earth
Fossil records of prokaryotic organisms showing similarities in formation
Genetic sequencing data for eukaryotes to show conserved processes

c.) polymerase chain reaction

- "unlike the original dna fingerprinting method, dna profiling does not use restriction enzymes to cut the dna. instead it uses the polymerase chain reaction (pcr)? to produce many copies of specific str sequences. pcr is an automated procedure that generates lots of copies of a specific sequence of dna."

it's c. (to reduce the greenhouse effect/carbon gasses)

c. heat from the poles back down towards the equator.