Q: Given a scientific passage and an answer, generate a question for the given answer.
Passage: Courtesy of the U. S. National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) Program. Lymph capillaries collect the flood the leaks from blood capillaries and is slowly returned to the cardiovascular system . Answer: cardiovascular
A:
Lymph capillaries collect the fluid that leaks from blood capillaries and slowly return it to what system?