how can a planetary nebula be identified? select the two correct answers..

Question

a. spherical shape
b. dark area
c. central star remnant
d. diffuse edges

Answer 1

The two correct answers for identifying a planetary nebula are:

a. spherical shape
c. central star remnant

Planetary nebulae typically exhibit a spherical shape and contain a central star remnant, which is the hot core of the star that expelled its outer layers.