Final answer:
The +20 nC charge will have 20 electric-field lines since the number of lines is proportional to the charge's magnitude. The MRNA sequence translates to a peptide 4 amino acids long due to the 4 codons present in the sequence.
Step-by-step explanation:
When considering how many electric-field lines come out of a charge, the number is proportional to the magnitude of the charge. Since the question gives us a baseline of 5 electric-field lines for a +5 nC charge, we can deduce that the number of field lines should be directly proportional to the amount of charge. Therefore, a +20 nC charge, which is four times greater than the +5 nC charge, should have four times the number of electric-field lines. Hence, the correct answer is d. 20 field lines.
As for the translation of an mRNA sequence into a peptide, each three-nucleotide codon corresponds to one amino acid in the peptide chain. Given the sequence 5'-AUGGGCUACCGA-3', which contains 12 nucleotides, there would be 12/3 = 4 codons, thus the peptide would be 4 amino acids long. Therefore, the correct answer is d. 4.