Some substances look alike and the density can help you determine which is which. It also helps to tell which is heavier than the other.
-- <span>The gravitational force that you feel when you stand on the surface
of a planet depends on the planet's mass and size. It has </span><span><span>nothing
to do with the planet's orbit. (</span>Of course,"size" is also related to the
planet's mass, density, and surface area.)
-- One possible cause of deforestation is the removal of trees without
adequate replanting.
-- According to Hubble’s Law, the farther away a galaxy is, the faster
it is moving away from us
-- Electromagnetic energy can be defined as energy that moves at
the speed of light. If you conduct experiments to determine whether
the electromagnetic energy is moving in the form of particles or waves,
you find that it behaves as both.</span>
Velocity, because if an object is in motion with no direction we will consider it as speed, but if it has direction we will consider it as Velocity. Hope it helps
