Answers: 1 .The difference in the brightness of two stars with the same surface temperature is attributable to their sizes.( last choice)
2.Most responsible for the formation of a star is gravitational force.(second choice )
3. Blue ( last choice)
4.
A spinning neutron star that appears to give off radio wave pulses is called a pulsar ( third choice)
5.Greater redshifts in the spectra of galaxies indicate faster speeds ( first choice)
Your answer is nitrogen fixing bacteria
let me know if you have any further questions
:)
Plate tectonics is believed to be the correct answer
