Answer:
There are both dominant and recessive alleles for different traits. Dominant alleles often times tend to be shown as a physical trait in offspring. This is because if one parent gives a dominant and the other a recessive, the dominant will become the physical trait that is expressed. On the other hand the recessive will not be shown. For example: an offspring may have the same eye color as a parent, but also have a hair color that neither parent has. This would assume that both parents had a recessive allele that was passed to the child for hair color. Meaning the parents carried the allele for the trait but did not physically exhibit it themselves.