การฟัง TOEFL

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Listen to part of a lecture in a biology class. The professor is discussing animal communication. Professor: Today we're going to look at how some animals use chemical signals, specifically pheromones, to communicate. Pheromones are chemicals released by an animal that affect the behavior of other members of the same species. For example, ants release pheromones to mark trails to food sources. When an ant finds food, it leaves a chemical trail, and other ants follow that scent. But pheromones aren't just for finding food. In many mammals, pheromones play a role in mating. Female moths, for instance, release a sex pheromone that can attract males from miles away. Interestingly, some animals also use pheromones to signal danger. When a wounded fish releases a chemical into the water, nearby fish will flee. So, pheromones are quite versatile. They can indicate food, reproductive readiness, or threats. However, unlike visual or auditory signals, pheromones can linger in the environment, which means they might be less immediate but can have longer-lasting effects.