Answer: A scenario often presented to introductory physics classes is that of a "gravity tunnel" — a tube drilled from one side of the Earth to the other through the planet's center. The answer taught for nearly a half-century for how long a fall through such a hole would take was about 42 minutes and 12 seconds.
Explanation: However, solar and lunar gravity, which also perturb orbiting satellites, would eventually pull you into the tunnel wall anyway [source: Darling ]. Strike a chord: Fun fact: A straight line from any point to any other point through the planet would take the same amount of time to fall through like a tunnel through Earth's center.
The answer is Mutations. It is the <span>type of selection on a polygenic trait that increases variation in the trait. Mutations </span>increase genetic variation, which is needed for natural selection to bring about evolutionary change. When a cell divides, it makes a copy of its DNA — and sometimes the copy is not quite perfect. That small difference from the original DNA sequence is a mutation<span>. </span>