Prokaryotic cells are simpler than eukaryotic cells. This is because prokaryotic cells have a single circular chromosome, no nucleus, and few other organelles. Eukaryotic cells have many chromosomes inside a nucleus, and they also have more organelles.
Building models doesn't actually help scientists observe phenomena. Scientists build models to describe how nature and systems operate then make observations to see if their models match what they observe. Models which don't match what they observe are either alterated or scrapped. Good models are kept and used by the scientific community.
The genotypes of its gametes would be TS, tS, Ts, and St. This would mean the answer would be C. Hopefully this helps you.