How can there be more than one possible genotype for an observed phenotype?

In the water cycle , when does water undergo a chemical change

The fruit of a certain plant is sweet and fleshy. the seeds of this plant have a seed coat that is fairly tough. the seeds germinate better if they are exposed to acid, or scarification. what is the most likely type of dispersal for this seed? water animal wind

Why did adult crab numbers decline in he ecosystem, even though sea stars were still available?