Answer: Although the best-known cause of a mass extinction is the asteroid impact that killed off the non-avian dinosaurs, in fact, volcanic activity seems to have wreaked much more havoc on Earth's biota. Volcanic activity is implicated in at least four mass extinctions, while an asteroid is a suspect in just one. Examples, of mass extinctions are Permian extinction of marine species, and Cretaceous extinction of various species, including dinosaurs.
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Answer:
In the backrest use materials where it is easy to clean and where they do not absorb fluids, in this way it would be cooler, such as an ecological leather simulator.
And in the armrest as well, but in both areas we must not rule out that if or if it should have even a minimum of padded surface so that the patient or the person who spends most of the day in the wheelchair does not suffer from joint pain.
Explanation:
Some wheelchair factories also implement modern chairs where they are made of stainless steel structures lined with padded material with perforated fabrics that allow breathing and aeration of body areas that have contact with the fabric.
Answer:

Explanation:
Hello there!
In this case, according to the given information it will be firstly necessary to set up the chemical equation taking place:

We infer we need to calculate the moles of NH3 by using both of the moles of N2 and H2 at the beginning, in order to identify the limiting reactant:

Thus, since hydrogen yields the fewest moles of ammonia, we conclude that we are just able to yield 4 moles of NH3.
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