Which were the earliest oxygen-producing life-forms? a. cyanobacteria. b. seaweed. c. dinosaurs. d. ferns.

image result for describe the various types of gene mutationsghr.nlm.nih.gov

the types of mutations include: missense mutation: this type of mutation is a change in one dna base pair that results in the substitution of one amino acid for another in the protein made by a gene. nonsense mutation: a nonsense mutation is also a change in one dna base pair.

explanation:

the index of refraction of the second medium is higher. i just took the test trust me !