探究：酸性水对花卉的生长有影响吗？(提示：酸性水可采用pH小于5.6的水，也可以用家用醋与水以1：10的比例配制。)
［作出假设］酸性水对植物的生长有影响。
［制定计划］1．选取两株相同的花卉，在种植的时候，除了水的因素以外，其他都采取相同的方法。2．在平时浇水的过程中，一株用正常的水浇，一株用酸性水(pH小于5.6的水，也可以用家用醋与水以1：10的比例配制)浇。
3．不断观察两株植物的生长情况，并记录。
［实施计划］1．按照计划的实验方案进行实施。
2．不断观察两株植物的生长情况，并记录。
［得出结论］酸性水对植物的生长有影响。
［表达与交流］与班级同学交流你的探究过程和结果，并在教师的指导下，进一步完成你的探究，可根据探究过程和结果，写出小论文。
| I watched as Dr. Ian Stead, the archaeologist in charge of the excavation, began carefully removing the peat with a clay modelling tool. X-rays taken through the box while it was at the hospital revealed ribs, backbone, arm bones and a skull (apparently with fractures). However, the bones showed up only faintly because acid in the peat had removed minerals from them. Using the X-rays, Stead started on what he thought might be a leg. By his side was Professor Frank Oldfield, of Liverpool University, an expert on peat who could identify vegetation from stems only a fraction of an inch long. "Similar bodies found in bogs in Denmark show signs of a violent death," Stead said. "It is essential for us to be able to distinguish between the plant fibres in peat and clothing or a piece of rope which might have been used to hang him." As Stead continued his gentle probing, a brown leathery limb began to materialize amidst the peat; but not until most of it was exposed could he and Robert Connolly, a physical anthropologist at Liverpool University, decide that it was an arm. Beside it was a small piece of animal fur — perhaps the remains of clothing. Following the forearm down into the peat, Stead found a brown shiny object and then, close by, two more. Seen under a magnifying glass, he suddenly realized they were fingernails— "beautifully manicured and without a scratch on them," he said. "Most people at this time in the Iron Age were farmers; but with fingernails like that, this person can’t have been. He might have been a priest or an aristocrat." Especially delicate work was required to reveal the head. On the third day, curly sideburns appeared and, shortly afterwards, a moustache. At first it seemed that the man had been balding but gradually he was seen to have close-cropped hair, about an inch or two long. "This information about his hairstyle is unique. We have no other information about what Britons looked like before the Roman invasion except for three small plaques showing Celts with drooping moustaches and shaven chins." The crucial clue showing how the man died had already been revealed, close to his neck, but it looked just like another innocent heather root. It was not recognized until two days later, when Margaret McCord, a senior conservation officer, found the same root at the back of his neck and, cleaning it carefully, saw its twisted texture. "He’s been garr0tted." She declared. The root was a length of twisted sinew, the thickness of a p string. A slip knot at the back shows how it was tightened round the neck. "A large discoloration on the left shoulder suggests a bruise and possibly a violent struggle," Stead said. |
Why did the researchers think the man was possibly a priest
A．(A) He had closely-cropped hair.
B．(B) His coat was fur-lined.
C．(C) He had a drooping moustache and shaven chin.
D．(D) His fingernails were well looked after.