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

[Q]: Passage: Kevin Walsh. Cows are able to digest grass with the help of the bacteria methanogens in their gut . CC BY 2.0. Answer: bacteria
[A]: A type of what in a cow's gut enables the animal to digest grass?

[Q]: Passage: Gases are also capable of dissolving in liquids. There are many examples of this in our everyday lives. For example, carbonated beverages contain dissolved carbon dioxide. We notice this when bubbles come out of solution when the beverage is opened. Another example is when oxygen from the air we breathe dissolves in our blood, where it is transported throughout the body. Fish and other aquatic organisms use gills to capture dissolved oxygen from their environments. Answer: oxygen
[A]: Fish and other aquatic organisms use gills to capture dissolved what?

[Q]: Passage: Acid-base reactions involve a transfer of a hydrogen ion instead of an electron. Acid-base reactions, like the one below, are also not redox reactions. Answer: hydrogen ion
[A]:
What is transferred in an acid-base reaction