ANSWER IS : A troposphere
<em>The answer is: D) collecting data</em>
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<em>During this process , researchers would use their observational skills and record every notable occurrence that happen to the variables.</em>
<em>The focus on this process is simply to add all relevant data without making any analyzation. That process come later on after the researchers started to change the variables in order to see whether it would create a correlation.</em>
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<u><em>Hope this helps!</em></u>
<u><em>Please mark brainliest!</em></u>
Vaccines introduce small amounts of dead viruses or harmful cells into the body in order to teach the body how to effectively fight said virus/cell
Abiotic factor means no living so your answer is water :)
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