Land animals are believed from sea animals.
A. to have developed
B. to have been developed
C. having developed
D. having been developed
网友回答
(答案→)A. to have developed
B. to have been developed
C. having developed
D. having been developed
解析：考查非谓语动词。句意：陆地动物被认为是由海洋动物进化而来的。根据句意可知事情已经发生，故用不定式的完成时，选A。