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Actually no. Dark matter is sensitive to gravity as any other particle. It cannot be seen as 'opposite' or anything like that.

I stated in "simpleton" terms as if you were to explain the concept to a bunch of school age children you would have a easier time making a contrast to gravity.

Okay I now see what you meant. The degree of simplification you were asking was not clear to me :)

I think the best way to explain that is that you have visible matter on the one hand, and something invisible (aka dark) on the other hand, the dark stuff living its live unconnected to us.

Gravity is special as in the sense it acts the same for what is visible and dark, and that it is also one the few observable ways where both dark and non-dark stuff can have a talk with each other.

I hope this is better ;)