墨子周游列国时带了三大车竹简,出行不便。导致这一现象发生根本变化的发明是( )
Marry doesn't like to go to the zoo, because she is afraid ______ tigers.
如图是比较归纳昆虫、两栖动物、鸟类生殖和发育的相同点和不同点,请据图回答问题