An individual who is a carrier for recessive genetic disorder but does not have symptoms of the disorder is

This individual is a healthy carrier.

A healthy carrier (sometimes called asymptomatic carrier) refers to a person whose organism is infected by a microorganism (virus, bacteria, parasite) without presenting any clinical manifestation.

This absence of reaction may result either from a weakness of the infectious agent or from the effectiveness of the defenses of the subject.

Nevertheless, a healthy carrier can transmit a disease to other people. This is for example the case of hemophilia or certain genetic pathologies.

i'd say that the moon rock is about 2.2 billion years old.