Which portion of the earth is believed to generate it's magnetic field

What is the result of the greenhouse effect? a. heat is deflected from the atmosphere. b. heat is released from the atmosphere. c. heat is kept in the atmosphere. d. plants are able to grow in the tropics where the air is the heaviest.

Where does the availability of water pose the greatest problem

Under which condition below would u expect a coarse-grained intrusive rock like diorite to form?