<span>Nuclear fission is either a nuclear reaction or radio active decay process in which nucleus (the center) of an atom splits into smaller parts called nuclei. This is an extremely exothermic reaction (i.e a reaction which produces heat) resulting into release of massive amount of energy in the form of heat and sometimes light. The reaction produces much more energy as compared to a similar mass of a conventional fuel, such as Petrol/Kerosene/Petroleum Gas etc. This makes Nuclear fission an extremely dense and at times very destructive source of energy. Some common elements capable of Nuclear fission are Uranium, Plutonium etc. Though in modern days Nuclear Fission are finding application in being a source of energy (such as a Nuclear power plant), but they are also used in destructive format as Nuclear Bombs and it's one of the top most imminent threats to the existence of humanity in future (in the event of a Nuclear war).</span>
Explanation:
It is given that, the Average Speed of the orbiting space shuttle is 17500 miles/hour.
We need to convert the speed in kilometers/
second
We know that,
1 mile = 1.609 km
or
1 km = 0.621 miles
1 hour = 3600 seconds

Now cancel the miles in numerator.

So, 17500 miles/hour is equal to 7.82 km/s.
Answer: 2) Electron X absorbs energy when it changes to a higher energy level.
Explanation:
The electrons in an atom exist in various energy levels. When an electron moves from a lower energy level to a higher energy level, energy is absorbed by the atom. When an electron moves from a higher to a lower energy level, energy is released (often as light).
Answer:
Enzymes
Explanation:
Enzymes are proteins that can act as catalysts in the body.