What can the fossil record show us that our daily observations cannot?

Many kangaroo rats live in the sonoran desert of the southwestern united states. they have a variety of adaptations for living in the desert. under which circumstance would the kangaroo rats of the sonoran desert be most likely to develop new adaptations by natural selection?

Mutations associated with albinism affect proteins involved in synthesis

Describe the response the kidneys have to dehydration and excessive water intake. what happens to the concentration of urine in each case ?