Read the passage carefully then answer the questions.

The environment is the most important thing for our life. The environment is the air we breathe, the water we drink and is everything we need for our life. This pollution affects the health of living things.

But only we can change it and solve it. First, we can use recycled paper to help save trees. Second try to avoid buying plastic. To protect the environment we also have to save energy.

Finally, we now know that environment is the most important thing for life. Everyday we invent and find more and more way to protect the environment. I hope that in the future the earth will be cleaner.

Questions

What can we use to help save trees?

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Đường cong trong hình bên là đồ thị của một hàm số trong bốn hàm số được liệt kê ở bốn phương án A, B, C, D dưới đây. Hỏi hàm số đó là hàm số nào?

A.  y = 2 x - 1 x + 1

B. y = 2 x + 1 x - 1

C. y = 2 x + 1 x + 1

D. y = 1 - 2 x x - 1