A volcano erupts quietly if it's magma is low on silica. Low silica magma will be very thin, runny, and will flow easily, so the gases in the magma will bubble out gently. Hope this helps!:)
They may be changed because they may find evidence of some thing that will change their perspective on things.
Answer:
Explanation:
Given
Free fall acceleration on mars 
Time Period of pendulum on earth 
Time period of Pendulum is given by

for earth



(b)For same time period on mars length is given by


