North and south america became connected at the isthmus of panama, which led to the migration of predators south. which geological theory explains this phenomenon?

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?

Each pair of clay balls represents two planetesimals. if each planetesimal is composed of the same material and is separated he the same distance, which pair experiences the frayed gravitational attraction?

Which zone within the open-ocean zone is home to the most organisms? deep zone surface zone intertidal zone transition zone