Which statements describe prominences? Check all that apply. Prominences are dark, cool areas on the surface of the Sun.
Prominences are composed of cool, dense gas.
Prominences can disturb radio communications on Earth.
Prominences cycle over an 11-year period.
Prominences are loop shaped.
Prominences appear in groups.

A prominence refers to a bright, large, gaseous feature projecting externally from the surface of the Sun, usually in a loop shape. Prominences are attached with the surface of the Sun in the photosphere and elongate outwards into the corona of the Sun.

The prominences are related to the discharge of the high energy constituents called a solar flare. These solar flares have been considered to influence electronic communication as their energy blends up the upper atmosphere of the Earth, making the radio transmissions weak and noisy.

Hence, the correct statements are prominences can disturb radio communications on Earth and prominences are loop-shaped.

the duration of a photographic flash is related to an rc time constant, which is 0.100 μs for a certain camera.

not too sure thinking all accelerations are pointed down