In the very distant geological past, all animals were aquatic. The very first vertebrates or animals with backbones, of which we have any fossil record, lived in water. These vertebrates, the fish, were adapted to underwater living. Their streamlined bodies were covered with scales to reduce surface friction: they had muscular tails so that they could swim swiftly in such a dense medium as water; and they were endowed with gills for breathing underwater. Descendants of fish-type ancestors crossed the seashore barrier and accommodated themselves to life on land. As amphibians, they possessed limbs instead of fins and lungs instead of gills. But they never became completely free of the bonds that tied them to the water; even today many amphibians return to the water to lay their eggs. Millions of years after the first clumsy amphibians crawled over the land, newer types of land dwellers appeared, these animals give rise to the present-day reptiles and mammals. They were completely converted for land dwelling, with bodies and biological activities far different from those of fish. With these special adaptations, mammals have been able to colonize the woods and meadows, the deserts and high mountains, often far removed from the sea.

Fish are suited to underwater life because of their ______

Câu hỏi liên quan

• How did Juliette Davidson benefit from the experience of her first job?

• Which statement would the author probably agree with?

• In what way is Juliette’s current job better her first job?

ZUNIA12

• Which of the following is NOT true about life in the future?

• A paragraph following the passage would most probably discuss_________.

• The author uses the word “But” in paragraph 4 to ______.

• The word “alarmingly” in paragraph 2 is closest in meaning to ____.

• In order to operate a computer, a student does not have to be _______

• This article is about ________.

• The writer himself __________ .

• Facial expressions __________.

• Why did John read about aeroplane?

• Which “reply” CLOSET in meaning to?

• Which of the following statement is TRUE about the passage?

• The word "frustrating" in paragraph 7 is closest in meaning to ______.

• “Bricks” are mentioned in paragraph 3 to indicate how _______.

• The word 'sensational' is closest in meaning to __________.

• The word "symptoms" is closest in meaning to______________.

• This article is about ................

• Why do people say that African women’s lives are hard?