Final answer:
Collateral circulation growth and extent is attributed to chronic ischemia, which stimulates the development of new blood vessels as a compensatory mechanism for maintaining blood flow to the affected tissue.
Step-by-step explanation:
Collateral circulation growth and extent is attributed to d. Chronic ischemia. Collateral circulation refers to the development of new blood vessels that can bypass a blocked or narrowed artery, allowing blood flow to reach the affected tissue. Chronic ischemia, which is a prolonged decrease in blood supply, stimulates the growth of collateral circulation as a compensatory mechanism to maintain blood flow to the tissue.