In a protein-coding region of DNA, a mutation that replaces a single nucleotide, but does not change the resulting amino acid, is likely to be:

the sphincter muscles at the end of the digestive tract is the anus.

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

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds