1.there are than 350 different kinds of sharks, such as the great white and whale sharks (many) 2.fossils show that sharks for 420 million years , since the early silurian (exist) 3.the fins of for stabilizing,steering , lifting and swimming(use) 4.some new kinds of sharks over the past ten years (find) преобразуйте слова чтобы они грамматически подходили содержанию текста
1. more 2. have existed 3. are used 4. have been found