Why do you lose balance while standing on a bus often. Need a expert to answer this. Must choose if 1st 2nd or 3rd Newton Law. And explain Please help.

The loss of balance while standing on a bus often is due:

Explanation:

The third Newton law from Latin says: "Action is always opposed an equal reaction: or the two bodies on each other are always equal, and in opposite directions," which means that when a force is exercised in a direction by a body, the other body in the interaction exercises a force in the other direction. In the case of the person on the bus, when the bus makes a force forward, your body makes a force in the other direction (back), in a similar case, when the bus stops, its force in directed to the back, in that time your body make a force forward, in each case your body can lose balance because your center of gravity is directed in the same direction in which the opposite force to that of the bus moves.

d. air pressure decreases as altitude increases.