I guess it would have to be A
Answer:
lowering the activation energy needed for the reaction to start
The answer is directional selection
It is the mode of natural selection in which a single phenotype is favored, causing the allele frequency to continuously shift in one direction. The advantageous allele increases in frequency independently of its dominance relative to other alleles; that is even if the advantageous allele is recessive, it will eventually become fixed, changes the average value of a trait. Occurs most often under environmental changes and when populations migrate to new areas with different environmental pressures.
Answer:
The early atmosphere was mainly carbon dioxide and water vapour. Water vapour condensed to form the oceans. Photosynthesis caused the amount of carbon dioxide to decrease and oxygen to increase.
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