Question

If Huntington's disease is due to a dominant trait shouldn't 3/4 of the population have Huntington's while 1/4 has a normal phenotype

Answer 1

The frequency of dominant alleles for Huntington’s is significantly less than the recessive alleles, so few people will have the trait despite it being dominant.

Answer 2

Oh, I didn’t realize there were answer choices for this question.

A.
In large populations, Mendelian ratios are ineffective.
B.
Appearance of a trait in a population does not solely depend on its dominant or recessive nature.
C.
Natural selection is eliminating Huntington’s disease

But anyway, like I said, just because a trait is dominant doesn’t mean it’ll always appear the most often in the population. It also depends on the allele frequency.