<span>The correct answer is d: detached earlobes</span>
The phenotype is the result of genotype and its interaction with the environment. The phenotype is an observable characteristic of an organism's trait, such as its morphology. So, in this case, morphological characteristic of the earlobe is that it is detached.
Since stomata are affected by [CO2] and water vapor content of the air, an environment with high water vapor content (water potential) and high CO2 levels will likely have the highest #of stomata. I.e. when plants have readily available water source and ample CO2 in order to maximize photosynthesis. As far as geographic environment I think it varies quite a bit and there are competing hypotheses from what I understand
