30．Sheep on a remote Scottish island are gradually shrinking _______ global warming, according to a study published in the journal Science.

A. on account of　　 　　 B. by means of　　 　　　 C. in case of　　 　　　　　 D. in spite of

29．As is _______ known, a good knowledge of basic physics helps us better understand natural phynomenons.

　 A. universally　　　　　 B. specifically　　　　 C. adequately　　　　 D. completely