Answer:
The correct answer is: geography and UV radiation.
Explanation:
Skin variation occurred thanks to evolution, and was driven as a consequence of the geographical location of different populations of humans.
The humans that lived in hot and sunny places, closer to the equator, where much more exposed to the sun's ultraviolet radiation. In order to survive the amount of UV lights that they were exposed to, new humans in those regions were being born with a darker skin tone, which was rich in melanin (a brown pigment that protects us from the sun radiation).
Contrary to these humans that lived in the tropical areas, the humans that populated the areas that were closer to the poles, developed much lighter skin as a result of lower amounts of melanin in their skin. Since sun exposure in the poles is very limited, humans needed to receive as much as they could for the production of Vitamin D, and thus, their skins got lighter and less protected.
Answer:
The correct answer is - option C.
Explanation:
Chemical energy is the energy that every substance or chemical have and its not affected by the presence or absence of the enzyme, while the activation energy is the required energy to initiate for a chemical reaction. If the energy of the chemical reaction is less than the activation energy reaction will not take place.
Presence of a enzyme lowers the amount of the energy for the initiating the reaction which is activation energy and the chemical reaction takes place.
Thus, the correct answer is - option C.
Answer:
B. they bring cold , polar winds to the equator
Lungs, lung cells, lung tissues