Which phrases describe air pressure? select three options.
a)decreases with denser air
b)decreases as altitude increases
c)equals mass divided by volume
d)results from a column of air pushing on an area
e)decreases due to fewer air particles pushing down

The correct answer is - Life forms existed during the Cambrian period.

Explanation: The Cambrian period is a period when the life on Earth ''explodes'', lots of different types of animals and plants, as well as separate families of them, are evolving rapidly.One of those creatures that appeared in this period was the Paradoxides pinus. It was a trilobite that lived during the mid Cambrian. It had elongated semi-circular shape. It had an exoskeleton, so its outside was hard, but inside was soft and boneless. Its body was divided in numerous parts in order for it to be able to move properly and be more flexible.

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.

imagine a line passing through the center of earth that goes through both the north pole and the south pole. this imaginary line is called an axis. earth spins around its axis, just as a top spins around its spindle. this spinning movement is called earth's rotation. at the same time that the earth spins on its axis, it also orbits, or revolves around the sun. this movement is called revolution.