Choose the correct words a-d to complete the text.

Fly or be green!
Although air travel is more popular than ever, only 3% percent of the world's population chose this means of transportation in 2017, and only 18% have ever done so. (...)

(Cała treść tekstu, z uzupełnionymi lukami, została skopiowana do odpowiedzi.)

1. a. similar b. upward c. maximum d. downward
2. a. will have risen b. will be rising c. is rising d. is to rise
3. a. makes b. produces c. causes d. contributes
4. a. by b. about c. in d. over
5. a. likely b. due c. common d. significant
6. a. strongly b. deeplu c. considerably d. merely
7. a. exhaust b. renewable c. acid d. fossil
8. a. affect b. lead c. result d. cause