What are the three main parts of the circulatory system.

The parts of your circulatory system are your:

1)Heart, a muscular organ that pumps blood throughout your body.

2)Blood vessels, which include your arteries, veins and capillaries.

3)Blood, made up of red and white blood cells, plasma and platelets.

your answer is "the 1950's"

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.