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

[EX Q]: Passage: Most chemical reactions in organisms take place in an environment that is mostly water. Answer: water
[EX A]: The environment where most chemical reactions in organisms takes place consists mostly of what?

[EX Q]: Passage: Landslides are the most dramatic, sudden, and dangerous types of mass wasting. Landslides are sudden falls of rock; by contrast, avalanches are sudden falls of snow. Answer: landslides
[EX A]: What are the most dramatic, sudden, and dangerous types of mass wasting?

[EX Q]: Passage: Blood with wastes enters each kidney through an artery, which branches into many capillaries. After passing through capillaries and being filtered, the clean blood leaves the kidney through a vein. Answer: kidney
[EX A]:
After passing through capillaries and being filtered, clean blood leaves what organ through a vein?