Most environmental problems can be traced to three underlying causes; the number of humans on this planet, utilization of resources at a very fast rate and

Pollution

Most environmental problems can be traced to three underlying causes; the number of humans on this planet, utilization of resources at a very fast rate and pollution.

Pollution is the contamination of the environment by the introduction of any substance (pollutants) which may be liquid, solid or gaseous that makes the environment dirty and unhealthy. The major types of pollution include land pollution, water pollution, and air pollution. Others include noise pollution and light pollution.

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.