问题 选择题

“橘生淮南则为橘,橘生淮北则为枳”,造成这一差异的主要因素是(  )

A.光照

B.温度

C.空气

D.水分

答案

环境中影响生物生活的各种因素叫环境因素,分为非生物因素和生物因素.非生物因素包括:光、温度、水、空气、土壤等.生物因素是指环境中影响某种生物个体生活的其他所生物.非生物因素温度对植物的分布有着重要影响.橘在南方生长得得很好,在北方生长不好.主要是南方、北方温度不同造成的,橘是热带水果适宜生长在高温的南方,北方温度低不适宜橘子的生长,故淮南的橘子移种到淮北,就结不出甜美多汁的果实.主要是温度不同造成的.

故选:B

单项选择题 共用题干题
单项选择题

People have good reason to care about the welfare of animals. Ever since the Enlightenment, their treatment has been seen as a measure of mankind’s humanity. It is no coincidence that William Wilberforce and Sir Thomas Foxwell Buxton, two leaders of the movement to abolish the slave trade, helped found the Royal Society for the Prevention of Cruelty to Animals in the 1820s. An increasing number of people go further: mankind has a duty not to cause pain to animals that have the capacity to suffer. Both views have led people gradually to extend treatment once reserved for mankind to other species.

But when everyday lives are measured against such principles, they are fraught with contradictions. Those who would never dream of caging their cats and dogs guzzle bacon and eggs from ghastly factory farms. The abattoir and the cattle truck are secret places safely hidden from the meat-eater’s gaze and the child’s story book. Plenty of people who denounce the fur-trade (much of which is from farmed animals) quite happily wear leather (also from farmed animals).

Perhaps the inconsistency is understandable. After hundreds of years of thinking about it, people cannot agree on a system of rights for each other, so the ground is bound to get shakier still when animals are included. The trouble is that confusion and contradiction open the way to the extremist. And because scientific research is remote from most people’s lives, it is particularly vulnerable to their campaigns.

In fact, science should be the last target, wherever you draw the boundaries of animal welfare. For one thing, there is rarely an alternative to using animals in research. If there were, scientists would grasp it, because animal research is expensive and encircled by regulations. Animal research is also for a higher purpose than a full belly or an elegant outfit. The world needs new medicines and surgical procedures just as it needs the unknowable fruits of pure research.

And science is, by and large, kind to its animals. The couple of million (mainly rats and mice) that die in Britain’s laboratories are far better looked- after and far more humanely killed than the billion or so (mainly chickens ) on Britain’s farms. Indeed, if Darley Oaks makes up its loss of guinea pigs with turkeys or dairy cows, you can be fairly sure animal welfare in Britain has just taken a step backwards.

The first paragraph is written to()

A. put forward sound reason to care about the welfare of animals

B. emphasize the glory of the Enlightenment

C. introduce the Royal Society for the Prevention of Cruelty to Animals

D. provide background knowledge for the discussion to be expanded