Answer:
The sentences has been completed
Step-by-step explanation:
1.The team of biologists HAS BEEN STUDYING the effects of pollution on plants for years.
2.The government HAS TAKEN
measure to limit sea pollution by passing a new law.
3.Overfishing HAS CAUSED some species to become extinct over the years.
4.Ecotourism BEGAN to become popular when i was at university
5.The use of fossil fuels HAS INCREASED the amounts of carbon dioxide in the atmosphere.
6.The scientist BEGAN research on coral reefs since he left university.
7.Sea levels HAVE RISEN gradually in the last 10 years.
8.The journalist FINISHED
writting an article on the Amazon a month ago.