Answer: A substitution is a mutation that exchanges one base for another (i.e., a change in a single "chemical letter" such as switching an A to a G). Such a substitution could: change a codon to one that encodes a different amino acid and cause a small change in the protein produced.
Explanation: I know this is correct just trust me and please mark me as brainiest.
Answer: the scientist should ensure that the volume is measured in dm3(or L), the pressure in atm, the temperature in Kelvin and use the gas constant 0.082atm.dm3.K^-1.mol^-1