Answer:
(B) resemble structures formed by bacterial communities that are found today in some shallow marine bays.
Explanation:
Extant stromatolites represent real "living fossils" for they are decendents of ancient forms that are associated with one of the first living forms on earth. Particularly, stromatolites are real bacteria communities where the autotrophic organism of the community are represented by cyanobacteria, which live along with heterotrophic bacteria. This clearly indicates that fossilized stromatolites points to bacteria (prokaryotes) as the first living things on earth (dated with not less than 3.5 billion year old)
Nowadays, stromatolites with cyanobacteria allows to reconstruct and understand fossilized forms. These current structures live in shallow marines ambients (e.g. Australia) but also in continental salt flats (e.g. Argentina) where few others bacteria can survive to these extreme conditions (high light exposure and salt concentration).
Answer:
A mutation during protein synthesis may not affect the protein since the mutation causes a new code for the same amino acid, the protein will still function normally.
Explanation:
Protein synthesis depends on the transcription of DNA to RNA, and on the sequence of nucleotides in the chain, determining the triplets or codons that encode a specific amino acid.
In protein synthesis, when a mutation alters the codon, changing one nucleotide for another, it is possible that the mutation does not alter the amino acid and the protein functions correctly. This is because an amino acid can be encoded by several codons, as occurs with leucine, which is encoded by CUU, CUC, CUA and CUG.
<em> The other options are not correct because one mutation does not give better amino acids or more powerful proteins.</em>
Answer:
B
Explanation:
The repressor protein blocks the genes from making mRNA
