In hot temperatures , muscles loose water content due to dehydration , impairing their function. In cold temperatures , blood flow is reduced , impairing function

yes

Unless it is significantly blocking the winshield and impairing visibility, you'll be fine.

You are breaking the law - contributing to the delinquency of a minor - impairing their health and well-being - etc..

is caused when blood flow to an area of the heart is decreased, impairing the delivery of oxygen and vital nutrients to the heart muscle cells.