【简答题】如图所示为某种群在不同生态系统中的增长曲线模式图,请据图回答下列问题: (1) 如果种群生活在一个理想的环境中,种群数量是按 a 曲线增长,但实际上,在自然环境中 和 都是有限的。若按 a 曲线方式增长其增长率 。(增大或减少或不变) (2) 在一定环境中,除上述影响外,种群数量还受其他环境因素的限制。如无机环境方面主要是 的影响。种群数量增长按 b 曲线方式增长,最多达到 K 值时,此时种群增长...
【单选题】Despite such a big different in the _____ towards what one eats, there is no doubt that people in the west regard Chinese food as something special. [ ]
【简答题】—Tom says he is too tired to go on. —He can’t be.He ____for an hour. A.just worked B.has only been working C.has just worked D.had only been working