A fish pushes water backwards in order to move forward is a good example of Newton's 3rd Law.
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Terminal velocity is the maximum velocity attainable by an object as it falls through a fluid (air is the most common example). It occurs when the sum of the drag force (Fd) and the buoyancy is equal to the downward force of gravity (FG) acting on the object.(Wikipedia)
A carbide ion is an anion of carbon atom with two carbon atoms with a triple bond connected to each other. Since this carbide ion is a negatively charged ion, in order to convert carbide ion to its neutral carbon atom, it has to give up/remove four electrons.