According to the plate tectonic theory, a plate can be made up of

1.A Characteristic refers to the distinctive qualities that make up an individual. A trait, on the other hand, is a feature of an individual which is inherited. The main difference between a characteristic and a trait is while a characteristic needs to be built by a person and absorbed, a trait comes genealogically.

2.Technically, they can but you don't have to be related because you can have things in common with another person with are personality traits , and if they have different skin colors it doesn't matter , and you can still have many traits in common , because my sister is darker than me a lot but we still share same traits.

3.The yellow color of the flower is heredity but the wilting is from the environment

and the tall stem could be both, heredity and environmental.