Marble is formed when intense heat and pressure is applied to limestone. what type of rock is marble?
a)
metamorphic
b)
sedimentary
c)
extrusive igneous
d)
intrusive igneous

Ascientist wants to determine the effect of a new type of gasoline. he fillsone car with normal gasoline and another identical car with the new gasoline.which is the control group? a. the new type of gasolineb. the car with the normal gasolinec. the car with the new gasolinethe amount of gasoline usedd. the amount of gasoline used

Crossing over is a method of (blank)?

There are fewer than 100 naturally occurring elements in the universe, but there are millions of different unified substances. explain how this can be true.