Answer:
True
Explanation:
When fossil fuels are burned, they release large amounts of carbon dioxide, a greenhouse gas, into the air. Greenhouse gases trap heat in our atmosphere, causing global warming.
Drugs interfere with the way neurons send, receive, and process signals via neurotransmitters. Some drugs, such as marijuana and heroin, can activate neurons because their chemical structure mimics that of a natural neurotransmitter in the body.
Answer:
in controlled experiment an independent variable is systematically manupulated and dependent variable is measured ; any extraneous variables are controlled
