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Answer: A</h2>
Explanation because the distance covered is equal time intervals is the same or equal.
There are two external force acts on the chair.
1. The force due to earth gravity, acts in the downward direction.
2. Reaction force of the gravity, which acts in the Upward direction (Normal Force).
On every object, there is a force acts due to gravity of earth, which pulls the object towards the centre of earth, known as gravity force, always acts in the downward direction. Mathematically it's given as
F=mg
here, m is the mass of the object, and g is the acceleration of gravity.
To balance this gravity force, a counter force acts in the opposite direction, whose magnitude is equal to the force of gravity
C. Amount of oxygen
The others either change but don’t decrease or they increase.