Normally you would put the topic in the center of a diagram
Answer:
Mountains and bodies of water
Explanation:
Mountains and bodies of water protected empires as it was the mountains that served as a barrier that protected ancient China and was used as an invasion route by the Aryans into ancient India also water bodies provided agricultural facilities which helped in allowing the empires become more successful.
As the substance melts the particles have a higher chance of colliding with one another and also move much faster than when the substance is solid. This is because the particles have a higher surface area to move around. Also the arrangements of particles are free.
