To make an enzyme that it needs, the chemical mechanisms inside an E. coli bacterium make a copy of a gene from the DNA strand and use this template to form the enzyme. The E. coli might have thousands of copies of some enzymes floating around inside it, and only a few copies of ot...
In fact, basic aerodynamic tests are sometimes performed underwater. To put it simply, a salmon essentially flies through the sea, and a pelican swims through the air. The core of the matter is this: Even a clear sky isn't empty. Our atmosphere is a massive fluid layer, and the right...
【答案】 A 【核心短语/词汇】cross the river:过河 【翻译】—Jane是怎么样过河的?—坐船。 【解析】考查单词辨析。“cross”是动词,意思是:跨越,穿越;“across”是介词,意思是: 越过...。分析句子结构,在“does”的后面须接动词原形,故排除第三人称单数形式的选项B,再排除介词(across),所以选项A正确...
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Notable also are their pseudobulbs — water storage organs that balloon toward the base of each stem. Allow roots to dry between waterings as the pseudobulbs help them retain water relatively well. Cattleyas require bright light. Oncidium ...
Because the water won't squeeze into a smaller space, it gets forced through the body of the pistol to the narrow nozzle and squirts out with less force but more speed.Now suppose we could make a water pistol work in reverse. If we could shoot liquid into the nozzle at high speed, ...
The corridor traveled by Calvin and the other North Atlantic right whales has grown evermore crowded with fishing activities and busy shipping lanes. Plumes of contaminants flow from river mouths, and the underwater din of ship traffic probably makes it increasingly difficult for the whales to commu...
Density measure how compact a substance which is measured by diving mass by its volume. Buoyancy, on the other hand, is the force that a fluid exerts on an object that is submerged to it. A dense object will eventually sink in water and float if it is less dense than the fluid....
3. What is the woman likely to do? A. Make a phone call. B. Handle the problem. C. Have a rest. 4. Which tour does the man seem to be interested in? A. The evening tour. B. The half-day tour. C. The full-day tour. 5. Where are the speakers? A. At a canteen. B. ...
Watch the glorious underwater spectacle of the Sardine run -- the greatest shoal on earth. Courtesy Junko Kimura/Getty Images AsiaPac/Getty Images Dubbed “the greatest shoal on earth,” the sardine run on South Africa’s Wild Coast holds two titles – the world’s largest animal migration al...