D. Genetic variation increases the likelihood of an allele being present that is best suited for the environment.
Answer:
Explanation:
Given
Diver is at a depth of
inside the water
As we go down pressure increases due to the weight of liquid column above us
Pressure difference is given by 
Where
=density of liquid
h=depth
g=acceleration due to gravity
So external-internal pressure difference is


The atomic number of Copper is 29. So immediately we know that there are <em>29 protons </em>in the nucleus of each Copper atom, and <em>29 electrons</em> in the cloud surrounding the nucleus of each [neutral] Copper atom.
Copper has two stable isotopes ... ⁶³Copper and ⁶⁵Copper. So if the Copper atom you're holding in your hand is not radioactive, then it has either (63-29)=<em>34 neutrons</em> or (65-29)=<em>36 neutrons</em> in its nucleus. (There's never a need to round the number of neutrons, because there's no such thing as a <em>part </em>of a neutron.)
For one thing, an object that is not moving has no momentum, no matter how much mass it has. Fast objects are also difficult to stop. Bullets have a very small mass, but you wouldn't want to try and stop one! More speed means more momentum - momentum is directly proportional to velocity