instruction:
Given a scientific passage and an answer, generate a question for the given answer.
question:
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
answer:
A type of what in a cow's gut enables the animal to digest grass?

question:
Passage: Neurons that innervate the muscles of the respiratory system are responsible for controlling and regulating pulmonary ventilation. The major brain centers involved in pulmonary ventilation are the medulla oblongata and the pontine respiratory group (Figure 22.20). Answer: neurons
answer:
What basic structures of the nervous system innervate the muscles of the respiratory system and are responsible for controlling and regulating pulmonary ventilation?

question:
Passage: Did you ever see workers sandblasting a building to clean it? Sand is blown onto the surface to scour away dirt and debris. Wind-blown sand has the same effect. It scours and polishes rocks and other surfaces. Wind-blown sand may carve rocks into interesting shapes ( Figure below ). This form of erosion is called abrasion. It occurs any time rough sediments are blown or dragged over surfaces. Can you think of other ways abrasion might occur?. Answer: abrasion
answer:
Sandblasting a surface exemplifies what form of erosion?