Why does the efficiency of a complex machine decreases as more simple machines are used ?

By the law of conservation of energy, the energy input to a system must equal the output. However, when there are more moving parts in a machine, like in a complex machine, the energy converted to non-useful energy, such as the production of heat energy via friction, is increased. Therefore, the more the moving parts, the greater the losses of energy due to increased friction. This is why complex machines are less efficient.  

the most common type of reef is the fringing reef. this type of reef grows seaward directly from the shore. they form borders along the shoreline and surrounding islands.

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.