Answer:
Natural factors of population change can't be swayed by humans. So for an example of a natural factor take an Earthquake. As of right now we can only predict when Earthquakes will. Inevitably some things will still get damaged and that just can't be helped. An Artificial factor for population change is something specifically made by humans. For an example take a genocide. If some guy decides he wants to go on a killing spree, well all I can say is that is Definitely not natural. Hope that helped.
Rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius.
Answer:
1a : a reward or recompense for a particular act
b : a sum over and above a regular price paid chiefly as an inducement or incentive
c : a sum in advance of or in addition to the nominal value of something
bonds callable at a premium of six percent
d : something given free or at a reduced price with the purchase of a product or service
2 : the consideration paid for a contract of insurance
3 : a high value or a value in excess of that normally or usually expected
Lungs? Im not exactly sure about this one but hey i know its not feet
