Becuase there is a broad range of phenotypes for human height, the trait is an example of a polygenetic (poly = many, genetic = of genes) trait.
Due to the vast variations of human height, the trait is clearly not purely dominant or recessive. A dominant trait is due to a dominant allele (variation of a gene) which completely masks a recessive allele. If only dominant and recessive height phenotypes existed, there would only be two heights observed in humans!
Since there is such a vast variation amongst human heights, the trait is an example of a polygenetic trait. Polygenetic traits are traits that are influenced by more than one gene at multiple loci (locations) on one or more chromosomes. This results in a continuous distribution of traits within a species. Other examples of polygenetic traits include skin color, hair color, and weight.
There would be an increase in "Zebra" and "Gazelle" population. This is due to the fact that there wouldn't be as many lions to eat the zebras and gazelles, causing their repopulation to become more frequent.
