How does the authos introduction paragraphs 1-4 contribute to the authors explanation of the black death?

it emphasizes how severely the bubonic plague affected people and how quickly it killed them. It reveals how the bubonic plague was able to enter Europe without anyone knowing until it was a full pandemic.

Explanation:

the unsaturated fatty acid is a fat consist of one or more double bond in the fatty acid chain. if it contains one double bond then called as monounsaturated fatty acid however if, it contains more than one bonds called as a polyunsaturated fatty acid. true fatty acids are called unsaturated fatty acids as it reduces the risk of high blood cholesterol and good for health.