单项选择题
A．Each plant can live alone. B．Each animal can live alone. C．Everything living on earth cannot live without needing other living things. D．If living things want to live they must kill each other.
33（）A．necessaryB．wonderfulC．importantD．harmful
单项选择题33（）
A．necessary B．wonderful C．important D．harmful
Why is all life in danger Because （）break up the food c...
单项选择题Why is all life in danger Because （）break up the food chains.
A．Human beings B．animals C．plants and animals D．man and wild animals
Which living things can use sun energy directly（）A．Anim...
单项选择题Which living things can use sun energy directly（）
A．Animals. B．Plants. C．Both animals and plants. D．All living things.
