Green and brown frogs of the same species having slightly different visible characteristics would be considered phenotypic green and brown frogs of the same species having slightly different visible characteristics would be considered phenotypic niches morphs sister groups anomalies none of the above

The answer is morph. This could be caused by genetic polymorphisms or variation in the effect of the environment on each genotype. To be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population (one with random mating).

"d.) carbon dioxide and hydrogen sulfide"