Which of the following can enter and exit an open system? A. Energy but not matter
B. Matter and energy
C. Neither energy nor matter
D. Matter but not energy

What is the earliest point in the universe that we can observe? why can’t we see back further than this?

Alandscaper is shopping for landscaping materials. she wants to use materials through which water flows easily. which materials should she choose? check all that apply. clay gravel granite rocks with cracks loosely packed soil

The electric potential v is constant everywhere within a certain region of space. which statement below is true? the choices are: the electric field is also constant (but not zero) within the region. a charged particle placed within the region will experience an electric force. the electric field is zero everywhere within the region. the electric field varies from place to place within the region.