Which example best describes the influence of genetic factors?

A shrub with good access to sunlight is taller than other shrubs located in shaded are
A corn plant is the same height as another corn plant of a different variety
Horses the same size as its parents, and similar height, to other horses of the same breed that lives with on a farm
The adult offspring of a pair of deer is shorter than his parents, and obtained fewer nutrients when it was younger

The example of horses the same size as its parents, and similar height, to other horses of the same breed that lives on a farm best describes the influence of genetic factors. This is because the height and size of the horses are likely determined by their genetics, as they are the same breed and environment.