Which of these can be described as a system of stars, gases,
dust, and other matter that orbits a common center of gravity?

a. an asteroid

b. a galaxy

c. a nebula

d. a comet

(6.02 mc)what affect do marine protected areas have on environmental quality? they increase environmental quality by preventing resource overuse. they increase environmental quality by adding new species. they decrease environmental quality by removing all human activity. they decrease environmental quality by adding recycling facilities.