Which environmental change would most likely result in bullfrog offspring that are able to store more water than bullfrogs in previous generations?

There environmental change would only have to occur when their is a sudden change in the amount of water, which would be a larger amount of water because that’s the only reason the bullfrog would need to store more water to help this species survive. This is called structural adaptation, structural adaptations are the physical features of an organism to help survive the new environment.