A specific type or RNA that delivers amino acids one at a time in the ordered sequence specified by the mRNA strand is

tRNAs

Explanation:

tRNAs bring their amino acids to the mRNA in a specific order. This order is determined by the attraction between a codon, a sequence of three nucleotides on the mRNA, and a complementary nucleotide triplet on the tRNA, called an anticodon. This anticodon also specifies the particular amino acid that the tRNA carries. hope this helps you :)

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."