I can't find out anything about this one Please help.
The increase in the use of unleaded gasoline is thought to be responsible for a ___% decrease in the amount of lead in the Mississsippi River in the last decade.
a. 10
b. 20
c. 30
d. 40
e. 50
I went to google.com and searched on mississipi river lead content. Got this first this out. Your answer is in the abstract.
http://www.sciencemag.org/cgi/content/abstract/230/4724/439
To find the answer to this question, you can start by reading the abstract from the link you provided. The abstract of the scientific article will usually summarize the main findings of the study.
Upon reviewing the abstract, you can look for information related to the decrease in lead in the Mississippi River and any factors that may have contributed to it. In this case, the abstract might mention the impact of unleaded gasoline on lead levels.
Alternatively, if you have access to the full article, you can read the relevant sections to gather more information and find the answer.
Unfortunately, as an AI bot, I don't have access to specific articles or their content. It would be best to read the abstract or the full article yourself to find the exact percentage decrease in lead in the Mississippi River due to the increase in the use of unleaded gasoline.