Stars as large as Betelgeuse are very unusual. In contrast, Rigel, the bright, bluish-white star at the southwest corner of Orion, is smaller and much hotter than Betelgeuse. Although Rigel is smaller than Betelgeuse, it is still a super-giant star compared to the sun.
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(a) is false since antibodies are produced by body humoral immune system
In competition, males use feather color to warn potential rivals that they occupy a piece of territory.
