3. Вставьте слова в пропуски.

acid rain, ozone layer, global warming, greenhouse effect

1. The gradual rise in the Earth’s temperature is known as ……… .
2. When heat gets trapped in the Earth’s atmosphere, it is known as the ……… .
3. Scientists have found holes in the ……… , particularly over Antarctica.
4. Rain mixed with toxic chemicals from factories is known as ……… .​