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

[EX Q]: Passage: Mouth Brooding. Some species of fish carry their fertilized eggs in their mouth until they hatch. This is called mouth brooding. If you look closely, you can see the eggs inside the mouth of the cardinalfish pictured here. Answer: mouth brooding
[EX A]: Some species of fish carry their fertilized eggs in their mouth until they hatch; this is called what?

[EX Q]: Passage: Insects spread disease and destroy crops. However, they are essential for pollinating flowering plants. Answer: insects
[EX A]: What are essential for pollination, but can spread disease and destroy crops?

[EX Q]: Passage: The water Americans get from their faucets is safe. This water has been treated and purified. At least 20% of the world's people do not have clean drinking water always available. That's more than 1 billion people. They must drink water from where they can get it. Maybe straight from a river or pond ( Figure below ). Human wastes may be in the water. If that's the case, the water will probably contain pathogens. Pathogens are organisms that cause diseases. Answer: clean drinking water
[EX A]:
At least 20 percent of the world's people do not have a ready supply of what?