Select the odd one out w.r.t. hereditary characters in human beings.Brown eye colourFree earlobeNegative Rh blood groupDimpled cheek

The odd one out with respect to hereditary characters in human beings is "Negative Rh blood group".

Here's why:

1. Brown eye colour: This is a hereditary trait. The gene for brown eyes is dominant, which means if one or both of your parents have brown eyes, you are likely to inherit the same.

2. Free earlobe: This is also a hereditary trait. The gene for free earlobes is dominant. If one or both of your parents have free earlobes, you are likely to inherit the same.

3. Dimpled cheek: This is a hereditary trait as well. The gene for dimples is dominant. If one or both of your parents have dimples, you are likely to inherit the same.

4. Negative Rh blood group: This is not a hereditary trait in the same way as the others. Rh factor is a type of protein on the surface of red blood cells. Most people are Rh-positive. Rh-negative people do not have this protein. This trait is not dominant or recessive, but co-dominant. If a person has at least one Rh+ allele, they will have Rh+ blood. Only if a person inherits two Rh- alleles will they have Rh- blood. Therefore, it's not as straightforward as the other traits and is the odd one out.