In the broadest sense of the term, we have modified the genes of almost everything. We used selective breeding to breed the most resistant form of crops, the largest sized chickens, and others. In recent years we have even modified them through gene splicing and other methods. Nearly everything we eat, including including "organic" foods have been changed from their original DNA structure, in fact we do not even know anything's original genetic structure because of this. Genetic modification could also include mutations. Some crops have mutated due to pollution, disease, or other effects such as climate change. Without genetic modification our world would differ from what it looks like today.
Competition requires instant succession within organism but parasitism can still be a gradual process due to its types exo and endo
THE ANSWER IS COMPETITION
Hey there! :D
When we are talking about gametes, we can use a punnet square, or in this case, common knowledge. If two of the alleles for one phenotype are the same, we can infer there will only be two variations of the genotype. (because there are two dominant SS genes) We already know that "D" must be the answer. Firstly, there will be one allele for each gene, so there will always be an "S" and a "T" no "SS" or "tt" (when talking about gametes). That leaves us with B and D but there is no recessive "s" in the original genotype, so the answer must be "D".
I hope this helps!
~kaikers