A(n) is a rebellion meant to subvert the existing government.
a.
cartel
b.
extradition
c.
bicameral
d.
insurgency

Answergranite

Hope this shshf

1. why do astronomers think that there may be other advanced civilizations?
because  it was discovered that there are other planets like earth out there, able to  accommodate life forms.
2. what technologies are astronomers using to look for life on other planets? why?  
they  have used radio telescopes, but now they use laser telescopes   to track laser communications.