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.
⭐️Your body cells use the oxygen you breathe to get energy from the food you eat. This process is called cellular respiration. During cellular respiration the cell uses oxygen to break down sugar. ... When the cell uses oxygen to break down sugar, oxygen is used, carbon dioxide is produced, and energy is released.⭐️
Answer: Brain stem
Explanation:
The brainstem can be defined as a structure which is present in between the midbrain and the cerebrum. This controls the flow of information from the brain and the rest of the body. It also controls the functions like breathing, heart rate, consciousness, sleep and wake cycle and blood pressure. The brain stem consists of pons, midbrain and medulla oblongata.
<span>it the lactic acid and pyruvic acid I think</span>
