Answer to Question 1
ANS: C
A thrombus is a clot that remains attached to a vessel wall; a detached thrombus is a thrombo-embolus. An embolus is a bolus of material floating in the bloodstream. An infarction is death of tissue.
Answer to Question 2
ANS: C
Cerebral aneurysms often occur in the circle of Willis. Such an aneurysm is not associated with the vertebral arteries, the basilar artery, or the carotid arteries.