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10 months ago
1. 4.1 billion years ago - life appeared on the earth. And gradually began to develop.
2. 330 BC - dogs appeared on the ground. They were not friendly and like wolves.
3. 120 century BC - on the ground there were domestic dogs. A man could tame a dog.
4. 20th century AD - Russian scientist Ivan Pavlov conducted experiments on dogs. He studied conditional and unconditioned reflexes of dogs.
5. 21 century of our era - I had a problematic question "why dogs do not go to the museum?". In order to find the answer to this question, it is necessary that the dogs begin to speak.
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