Answer to Question 1
ANS: C
Alterations in vitamin K levels alter the effects of warfarin. A diet high in green leafy vegetables reduces the effectiveness of warfarin.
Answer to Question 2
ANS: A
Unfractionated heparin (UFH) is comprised of long-chain molecules that form tertiary complexes with antithrombin III, allowing for inactivation of IIa (thrombin) as well as factors Xa and XIa. In low dosages, UFH prevents the conversion of prothrombin to thrombin by its effects on factor Xa. In higher doses, UFH neutralizes thrombin, thus preventing the conversion of fibrinogen to fibrin.