Answer:
This is a question relating to Newton's 3rd Law of motion which states that "For every action, there is an equal and opposite reaction".
To move yourself in a certain direction while in water, you use a combination of arm strokes and kicks in a coordinated movement we call swimming.
As we are using these movements to push water away, an equal and opposite force is also acting upon us, pushing us towards the opposite direction of where we are pushing the water.
