Q: Fact: a cavern is formed by carbonic acid in groundwater seeping through rock and dissolving limestone
Question: the presence of which of these is required for the formation of cavernous chambers?

A: some carbonic acid

Q: Fact: an animal requires air for survival
Question: How essential is air for animals?

A: it is necessary

Q: Fact: the sun causes water to evaporate more quickly by adding heat
Question: Water will become vapor quicker in

A: Mercury

Q: Fact: a beak is used for catching prey by some birds
Question: What is used to catch prey by some birds?

A:
a bill