人之所以成为“万物之灵”,从行为方面分析,主要是因为人类具有最强的( )
A:捕食行为
B:学习行为
C:防御行为
D:繁殖行为
下图为气候对东北地区农业生产的影响图,适宜在东北农业基地大量种植的农作物有( )
Being happy is a skill that can be learned like a foreign language, and one way to ______ ourselves to be happy is to write down the little things that cheer us up each day.
下列性质中,等腰三角形具有而直角三角形不一定具有的是 ( )