Select the correct answer from each drop-down menu.

brass and bronze are both of copper because copper is the component in brass and bronze.

a.
alloys
composites
variations
void

b.
main
most dense
most expensive
only

Brass and bronze are both alloys(A) of copper because copper is the main(B) component in brass and bronze.

Explanation:

Brass and Bronze are used in our day to day life known as metal alloys.  Brass is an alloy of the metals like copper and zinc which has high percentage of metal copper with tin combined with it.  

Brass is dull yellow in color. Bronze is reddish brown in color. Brass was known to be present in 500 BC. Bronze was about 3500 BC known to be present.  Thus Bronze and Brass are both alloys of the metal copper since the main component in the brass and bronze is copper.

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.