Answer:
A. He has a large buildup of lactate in his muscles.
Explanation:
Ideally, our body cells, via the process of aerobic cellular respiration, need oxygen to break down glucose. However, during rigorous activities or exercises, oxygen can become unavailable for use. In this case, the body cells switch to use another way of cellular respiration, which is FERMENTATION.
This fermentation causes a build up of lactic acid/lactate (its byproduct) in the cells of the muscles being used, which physically causes a burning and aching sensation just as the case of this hiker. The climbing of the steep path is causing causing the fast usage of oxygen in his cells.
Answer:
This nucleus then acquires <u><em>one </em></u>electron to become electrically neutral.
Explanation:
Fusion :It is nuclear reaction which two or more than smaller nuclei combines together to form heavy nuclear.
A neutron combines with proton in order to make heavy electron that is fusion reaction is taking place.

The overall charge in the nucleus will be +1.And in order to neutralize this positive charge the nucleus will acquire single electron to become electrically neutral.
Answer:
<em>The definition of an organism is a creature such as a plant, animal or a single-celled life form, or something that has interdependent parts and that is being compared to a living creature. An example of an organism is a dog, person or bacteria. An example of an organism is one party in the political organism.</em>
Meteorite: If a small asteroid<span> or large </span>meteoroid<span> survives its fiery passage through the Earth’s atmosphere and lands on Earth’s surface, it is then called a meteorite. Another related term is bolide, which is a very bright meteor that often explodes in the atmosphere.</span>