植物茎往上长时表现出负向地性.The main stems of a plant show negative geotropism as they grow upwards.根系向地性变化可由缺磷等因素所诱导, 且存在著一定的遗传变异性.Root gravitropic responses are adaptive , inheritable traits induced by low phosphorus availability a...
prehistoric hunters and gatherers史前的狩猎者和采集者The brazil nut gatherers were paid only 2 to 3 percent of the New York wholesale price.这些巴西果采摘者所卖的钱仅为纽约批发价格的2%到3%。The earliest people were roving hunters and gatherers who made ...