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TPO 63- Speaking Question 3

Now listen to part of a lecture in a biology class.

Professor:

Okay, so let’s look at an example of this with insects.Take caterpillars for example.Some caterpillars have this ability. Now, say there’s a caterpillar crawling along on a branch in a tree, just minding its own business. And then some dangerous insect, like a wasp, flies toward the tree. The caterpillar could be in trouble. The wasp might try to eat the caterpillar. It’s a threat.

Now, a lot of other animals may not hear the wasp or know that it’s close by. But fortunately, for the caterpillar, there are these really tiny hairs on the caterpillar’s skin, little hairs that stick out into the air around the caterpillar. And when the wasp flies toward the tree, the beating of its wings makes a sound, which sends out vibrations, or small movements in the air, which make the caterpillar’s tiny hairs move, so it senses the presence of the wasp, so once the caterpillar realizes something is flying toward it and it might be a wasp, the caterpillar will just drop off the branch it’s been crawling on and fall to a lower branch or to the ground.

And in this way the wasp is likely to just fly right by without ever catching the caterpillar and the caterpillar will be safe.