How long does it take for sedimentary rock to melt into magma

Which of the following occurs after a natural or unnatural disturbance in an ecosystem

What can be said about farmers in highly developed countries? a) they have little or no negative impact on the environment. b) they practice subsistence agriculture. c) they are able to incorporate polyculture into their farming practices. d) they utilize organic farming techniques on a regular basis. e) they rely on large amounts of energy from fossil fuels.

How is the carbon cycle related to global warming ?