An engineer tests three new ceramic parts, each of which could potentially replace a steel part inside an automotive engine. The three parts, identical in size, are each made of a different ceramic compound. The parts are heated to the same temperature and placed under the same stress loads. At the end of the test, the engineer concludes Part B is the best for the job. What was the independent variable in this test? Select one:

a. dimensions of the parts

b. temperatures to which the parts were heated

c. the engine used to test the parts

d. the composition of the parts

carbon

explanation:

igneous rocks are formed by solidification of cooled magma (molten rock), with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks.  

the composition depends on the source magma. there are almost a thousand types of composition found till now.  

hope this

the earth is thought to have been formed about 4.6 billion years ago by collisions from a cloud of hydrogen, helium, rock, ice and other materials. these were pulled together by gravity to form objects in and around earth like- asteroids and small early planets called planetesimals.

so, the best possible answer to this question will be option d- to harden materials to form different parts of earth’s layers

haha

it's made from mineral oil