Answer:
A planetary nebula is a relatively small, ball-shaped nebula. A diffuse nebula is a larger nebula with an irregular shape.
Explanation:
A planetary nebula is created when a star expels its outer layers after it has run out of the fuel it had been burning. These outermost layers of gas expand into space, forming a nebula that is often in the shape of a ring or bubble and is relatively small.
Diffuse nebula is an area of space where a large amount of interstellar gas and dust accumulates. As this matter condenses, its temperature increases and stars begin to form, so its shape is irregular. They are, therefore, nurseries for stars, and because of this they are larger than planetary nebula.
