Answer:
B
Explanation:
It is important to only test one variable at a time because you need to be able to disprove or prove a problem with just one independent variable. When you have several variables in the experiment, it would be impossible to know which variable honestly caused the end result.
Magma that cools quickly forms one kind of igneous rock, and magma that cools slowly forms another kind. When magma rise from deep within the earth and explodes out of a volcano, it is called lava, and it cools quickly on the surface. Rock formed in this way is called extrusive igneous rock.
-58 °C
The melting point is the same as the freezing point.
Don't touch your eyes.
Never taste-test unless the teacher tells you to.
Do not touch anything without directions.
Wear safety goggles.
Wash your hands after each experiment.
Wear proper lab clothes.
Do not mishandle lab equipment.
Clean up your workplace.
Act serious; no horseplay!
Report accidents to the teacher right away!
Have a great day, scholar!