Sentences of a paragraph are given below in jumbled order. Arrange the sentences in the right order to form a meaningful and coherent paragraph.

A. Some stars exhibit starspots so large that an entire face of the star is relatively dark, while others display flare activity thousands of times more intense than that on the Sun.

B. X-ray observations that were made during the early 1980s yielded some rather unexpected findings. 

C. All-stars seemingly display active regions, including spots, flares, and prominences much like those of the Sun (see sunspot; solar flare; solar prominence).

D. They revealed that nearly all types of stars are surrounded by coronas having temperatures of one million kelvins (K) or more.