What are the energy transformations that occur in a cellphone that is plugged in? Is it an open or a closed system?

Which substance has non polar covalent bonds

The gulf stream is a warm water current that flows away from the equator to northern europe. witch of these does it cause. a. crashes of warm and cool water in the ocean b.colder climates near the equator c.large waves on the cost of europe d.warm climates in northern europe

What is true for a substance that releases energy