As the rare inherited trait can pass to some of the children and is suppressed in the rest it is most likely to be transferred by recessive alleles of either of the parent.
A recessive trait can be described as a trait that gets masked by a dominant trait. For a person to show a recessive trait in their phenotype, the genotype of the person must contain two recessive alleles for that trait.
The answer is indeed "Chromosome"! Next time pls pls pls post the answer choices so people could understand the problem !! If you have any questions feel free to tag me I'm always on :)
