The first person that answered is correct just to let you know!
Answer:
1. Life, exist 2. pre-existing cells.
Explanation:
The molecular clock is a figurative term for a technique that uses the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged. The biomolecular data used for such calculations are usually nucleotide sequences for DNA or amino acid sequences for proteins.
Explanation:
Answer:
cellular respiration...that's breathing out of humans
and through human activities like burning of fossil fuels...
Answer: Photosynthesis
Explanation: Photosynthesis removes CO2 from the atmosphere and replaces it with O2. Respiration takes O2 from the atmosphere and replaces it with CO2.
