A genetic modification for lack of a better term...the grapes are probly genetically modified to be seedless.
"house" or "environment"; the way different organisms interact with eachother.
Region A would be the warmest during daytime.
Region B is covered in trees which would keep the ground level cool.
Region C Is shaded off by buildings
Region D is near the water which would bring in cool winds.
Ima just assume it is a true or false question and say true, as to make an experiment valid, only one variable has to be tested.