I believe its b , hope it helps
A planetary nebula is a (ring-shaped) type of nebula formed by an expanding shell of gas around an aging star. *a planetary nebula is a type of nebula*. im not completely certain though. i might be wrong.
Answer:
Hydrosphere: all the waters on the earth's surface, such as lakes and seas, and sometimes including water over the earth's surface, such as clouds.
Biosphere: the regions of the surface, atmosphere, and hydrosphere of the earth (or analogous parts of other planets) occupied by living organisms.
Geosphere: any of the almost spherical concentric regions of matter that make up the earth and its atmosphere, as the lithosphere and hydrosphere.
Atmosphere: the envelope of gases surrounding the earth or another planet.
I don't know if that will help but hopefully it does
Explanation:
The length of each side of a decagon that is 65 units total, each side will be 6.5 units.
Decagon = 10 sides.
65 ÷ 10 = 6.5
