Standing water is not good for the environment so it needs to be vanished and shall no longer be around humans or animals that can catch the deadly disease malaria !
the answer to your question Is
A. all ready
⭐️The answer is⭐️
Think of the main idea as an —umbrella“ idea. It is the author's primary point about a topic. All other material in the paragraph fits under the main idea. In a paragraph, authors often present the main idea to readers in a single sentence called the topic sentence.