Question

ANIMAL BUILDERS Animals are great builders, using simple materials but employing sound engineering principles. Man has long used suspension bridges made of ropes of steel and concrete, which bear loads in tension. The webs of spiders provide the most vivid examples of animal structures built entirely in tension. Spider-web silk is so strong that many species of birds use it to build their nests. It has a stiffness index which is 30 times less than that of steel,yet has a stretching strength one and a half times as much as that of steel. Unlike steel, silk stretches to more than twice its original length before breaking. Beavers are natural engineers. They use tree branches to construct dams, the divided end being pressed into the walls. This apparently serves to collect stress from a broad area and to focus it into a single trunk embedded in the layers of earth at the bottom of the stream. The dams of the beavers have an angle of 45 degree on the downstream side. This enables the structure to bear not only its own weight acting downwards but also resist the lateral pressure of water acting on the upstream side. 1- Why can animals be called 'engineers' in real sense? 2- What is the best example of structures built in tension? 3- Silk is very elastic.' Justify according to the passage. 4. How can we say that beavers are natural engineers? 5- Pick the words having similar meaning of the given words from the passage. a) authentic (para 1] b) inserted [para 2]​

Answer 1

Answer:

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