A:64÷64
B:4×3
C:12÷3
D:21÷7
我国唐朝的张志和在《玄贞子》中记载了著名的“人工彩虹”实验:“背日喷乎水,成虹霓之状.”该现象产生的原因是 ()
The ______ of living areas makes wild animals become fewer than before.