For my project it says "Circle all physical characteristics that are used as a part of your country's boundaries"

I am doing the country of India so wwhat would be an example of the physical characteristic used for a boundary I suppose?

I'd start with the Himalayas.

Would rivers count

These are the boundaries I think there is : Bay of Bengal, Arabian Sea, is there more and are those right

Yes. Rivers can be physical boundaries.

Would this be correct : Arabian Sea, Bay of Bengal, Thar Desert, Ganges. Himalayas

Or do I have to name physical characteristics that are on the border

Yes they are boundaries. What about the Indian Ocean?

Is it all of those?

http://shyamathanniyil.blogspot.com/2011/02/all-about-india.html

Thank you

You're welcome.