Answer:
protective?
Explanation: i dont know what your answers could be but i would say whichever one has something to do with protecting the cities that have been used as an example because they were all built to protect. hopefully this is helpful and works for your answers!
Answer:
D. Caldera
Explanation:
Caldera
(noun)
a large volcanic crater, especially one formed by major eruption leading to the collapse of the mouth of the volcano.
Your answer would be as said above *Caldera*
Answer:
the ratio of resolution will be
Explanation:
We have given the diameter of Telescope A is 1 meter
And diameter of telescope B is 6 meter
We know that resolution of telescope is inversely proportional to diameter of the telescope
So 
We have to find the ratio of resolution of B to A
So 
So the ratio of resolution will be
Because of gravity... if you want a more detailed answer look it up on google!