question: a supernova is an exploding star. they're merging of black holes and neutron stars and are among the most violent events in the universe.
Capitalize this past sentence correctly.
A: A supernova is an exploding star. They're merging of black holes and neutron stars and are among the most violent events in the universe.

question: the french were quick to develop the c-trumpet that fitted quite well in the ideal french light sound.
Capitalize this past sentence correctly.
A: The French were quick to develop the C-trumpet that fitted quite well in the ideal French light sound.

question: that's the kind of unity we're after:people who were many and diverse all becoming one.
Capitalize this past sentence correctly.
A: That's the kind of unity we're after:people who were many and diverse all becoming one.