Given a scientific passage and an answer, generate a question for the given answer.

[EX Q]: Passage: The placenta allows nutrients and wastes to be exchanged between the mother and fetus. The fetus is connected to the placenta through the umbilical cord. Answer: umbilical cord
[EX A]: What connects the fetus to the placenta?

[EX Q]: Passage: The menstrual cycle includes events that take place in the ovary, such as ovulation. Answer: ovary
[EX A]: Ovulation takes place in what organ and is part of the menstrual cycle?

[EX Q]: Passage: When glass breaks, its physical properties change. Instead of one solid sheet of glass, it now has holes and cracks. Answer: its physical property
[EX A]:
Which property changes when a glass breaks?