What part of a microscope is considered as a revolving device?

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?

If the birth rate of a population of dolphins is 2.0, the death rate is 0.5, and the population size is 100, what is this dolphin's population growth?

The circles, or orbits, for electrons are called energy levels. each level can hold only a certain number of electrons. add electrons to each level until you can't add any more. how many electrons can each level hold?