The answer is the first option (a)
A. Phase changing. When phase changes nothing chemically changes about the substance, its still the same thing.
D. because matter is uniform through and cannot be separated into other substances by physical means.
Answer:
This effect is caused by increased levels of carbon dioxide, chlorofluorocarbons and other gases in the air, many of them released by human activity. greenhouse effect The warming of Earth's atmosphere due to the buildup of heat-trapping gases, such as carbon dioxide and methane.
Explanation:
