which is the most likely explanation for child exhibiting a heritable trait that neither parent exhibits?

Answer 1

The most likely explanation for a child exhibiting a heritable trait that neither parent exhibits is the presence of a recessive gene, which can be passed down from previous generations. Both parents may carry the recessive gene but not display the trait themselves if they have a dominant gene masking it. When both parents pass down the recessive gene to the child, it becomes expressed and the trait manifests in the child.