Can someone help me pls I'm so confused 2 Describe one negative and one positive effect that human activities have had on the ozone layer

3 Describe one negative and one positive effect that humans have had on acid rain.

4 Scientists think we should try to stop carbon dioxide levels rising. Why do they think this?

5 Describe two ways that we can stop the amount of carbon dioxide in the atmosphere rising

6 How could clouds and mirrors be used to stop Earth getting warmer?

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Recently, crops of vegetables such as lettuce and green onions have been contaminated, while they are still on the farm, with bacteria that cause food poisoning. how will science influence the way the government responds to prevent an increase in food-borne diseases? because science has shown that lettuce and green onions are not nutritionally valuable, the government may pass laws that ban the sale of lettuce and green onions. because science has shown that there is no way to prevent bacterial contamination, the government may pass laws that punish businesses that buy lettuce and green onions. because science has shown that the washing of hands prevent the spread of infectious diseases among people, the government may pass laws that require hand washing by everyone who handles food. because science has shown there are ways to find the source of the contamination, the government may pass laws that require farm practices that reduce the contamination of lettuce and green onions.

Which of the following must be true for a fossil organism to be useful as an index fossil? a. the fossil organism must be widespread geographically. b. the fossil organism must be abundant. c. the fossil organism must be limited to a short span of geologic time. d. all of the above.

All phases of matter may have a fixed mass