@mahadevprasad,
The answer is Newtons Third Law; for every action there is an equal and opposite reaction. There is no difference between bigger objects and smaller objects. Every object that has mass attracts any other object that has mass.
The Sun puts a force on the Earth. The Earth puts the exact same force on the Sun. The difference is that since the Sun has 333,000 times as much mass as the Earth, the Earth is effected a lot, and the Sun moves only a little.
This is one way we are finding planets in other Solar Systems. We can't see the planets directly... but we can see the very tiny "wobble" that is caused because the planets are tugging ever so slightly on the star that we can see.
By the way, you are exerting a very tiny gravitational force on the Earth. And, you are also putting a very tiny gravitational force on that cute guy or girl who sits next to you in class (too small to measure, but it is there). You can can say that you are attracting them

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