(a text in English for upper-intermediate)
Read the text and fill in the gaps with phrases A-G. There is one phrase you will not need.
How do you feel about crocodiles? Do you consider them fierce animals with brains as small as walnuts? This is not the right point of view for many reasons. They’ve obviously deserved some courtesy if not love. And the first reason is that they are much older than us, people, 
Indeed, the crocodile is one of the oldest animals on the Earth — they lived in the times of dinosaurs and haven’t changed much since then. It’s a live artefact and many scientists adore it for that. The famous British naturalist Charles Darwin, who invented the evolution theory, wrote that «it’s not the strongest species that survive, nor the most intelligent, but the most responsive to change.» The crocodile adapts to the environment perfectly 
Crocodiles don’t produce much energy themselves but rely on solar energy to heat the body and then move to shade or into the water if they need some cooling. Economical and practical, isn’t it? They are able to control their blood circulation system, i.e. to slow down the blood flow when necessary, [з]
The most amazing fact about crocodiles is that they are able to regulate the work of their heart. The fact is that unlike other reptiles, crocodiles have very complicated four-chamber heart. However, when they dive they make the heart work as a three-chamber one. The crocodile is carnivorous, which means it eats other animals and undoubtedly can be dangerous to people. However, 
Like powerful weapons crocodiles are deadly dangerous only to people who don’t know «how they work» and are ignorant of their lifestyle. The crocodile is definitely not a pet and wants to be taken seriously.
Once a worker in the Australian Zoo was badly injured by a crocodile. The man was careless enough to enter the hedged territory where the crocodile was kept. He wanted to trim the grass to make the territory look nicer and didn’t expect the slow looking crocodile to be so fast. The crocodile wasn’t hungry, but he reacted to the vibration caused by the trimming machine. Vibration is absolutely irresistible for a crocodile, 
After the accident the crocodile was sold to a private crocodile farm in Queensland, and still lives there. The old huge crocodile (it’s about 70 years old and four meters long) is a great attraction to tourists. The son of the owner of the farm, who guides tourists round the territory, doesn’t conceal his affection towards the crocodile. He comes very close to the pool, entices the crocodile ashore, and feeds it from his hand. It looks very risky, [б]
Knowledge, experience and love help him control the huge and scary creature.
Answer the questions:
- How can the crocodile use the environment very efficiently?
- How has it managed to survive through lots of catastrophes and climate changes?
- What can the young man do when he knows how the crocodile «works»?
- What makes the crocodile attack?
- Why do people present the crocodile as a source of fatal unavoidable evil?
- Why is the crocodile almost independent of the outer conditions?