A medium can be anything that a wave can pass through e.g the medium can be solid objects, air, water, etc.
Answer:
natural disasters
Explanation:
Drought.
Earthquake.
Flash flood.
Hurricane.
Tornado.
Wild fire.
Winter storm.
these are some examples, hope this helps :)
(a)- Time
(b)- Heat produced(i guess)
(c)- Material
this is what I think, hope it helps
