1.what is at the center of our galaxy?

2.explain how scientist study black hole since we can’t see them?

3.what part of the orbit do you comets come from?

You are working in the lab and are working with the same element but with varying isotopes of the element. you are working with c-11, c-13, c-14, and c-15. what is the average atomic mass of this element? (use periodic table) a- 12 b-15 c-14 d-13