Answer:
wind and smoke from factories
Explanation:
Answer:
The universe is expanding.
Explanation:
Following the theory that the universe was originated from a single heavily compressed and super hot point, and quickly expanded itself to what we see today, we can assume that the universe is still expanding.
According to the big bang theory, the remnants of that explosion still cause the planets and elements in the universe to move farther from one another, allowing the universe to continue its expansion. This expansion has become slower and slower over billion of years, and the scientific community doesn't know for sure if the expansion will go on forever, or if it will have an end.