Answer:
Mutations in genetic code occurs when DNA is being duplicated.Any changes in the base pairs leads to mutations by trasition or transversion. Change in amino acid leads to change in sequence and thus, mutation. This si carried on to new generation, if it takes place in germ cells.
A seems most probable.
Oceans are also deeper and larger then Seas.
With smelly feet, you can avoid people who are boring and dangerous (,like bullies),
