The four essential elements for life are

a.
carbon, hydrogen, oxygen and nitrogen
b.
carbon, hydrogen, oxygen and sulfur
c.
carbon, nitrogen, oxygen and sulfur
d.
iron, nitrogen, oxygen and magnesium

Error analysis: what might be the reason that some of your percentages didn't exactly match your predicted results? gametes aren't responsible for inheritance. mice don't have large litters, so the sample size was not large enough. the wrong type of mice were used.