What causes the earth’s magnetic field?
a.
currents in the earth’s liquid-metal outer core
b.
the mineral composition of the earth’s crust
c.
molten material in the mantle
d.
magnetic particles located at the earth’s poles

Why does the sun appear to be the brightest star in the sky? a- its apparent brightness is much greater than other stars. b- it burns more gas, making it brighter than any other star. c- it is the largest star in the galaxy, so it is the brightest star. d- its relative distance to earth is closer than the other stars.

How does concentration affect reaction rate

Which is an example of a reversible physical change?