You are right it’s D
Wish you luck
Streams that flow beneath melting glaciers leave long ridges of layered sediments, known as Esker. Eskers are formed within ice-walled tunnels by streams which flowed within and under glaciers. They tended to form around the time of the glacial maximum when the glacier was slow and sluggish and after the retaining ice walls melted away, stream deposits remained as long winding ridges.
Around 1 billion nerves reside in your body! The nerve cells unlike many other types of cells does not perform mitosis resulting in paralyzation. :)
A codon is a sequence of three bases found on the messenger RNA (mRNA) molecule which is translated to produce an amino acid. Each amino acid is coded by one or more specific codons. If the codon is changed through a mutation, the amino acid produced may be different. However, in this case, the other codons that produce Leucine are:
UUA, UUG, CUU, CUC, CUA and CUG
So the code CUU could mutate to CUC, CUA or CUG and leucine would still be produced.