input: OPTIONS:
- gases
- water
- liquids
- buffer Now, answer this question: Q: What are solutions that maintain a relatively constant ph when an acid or a base is added? A:
A:
output: buffer

input: OPTIONS:
- nitrogen
- warmth
- air
- water Now, answer this question: Q: What is needed by all known forms of life? A:
A:
output: water

input: OPTIONS:
- forehead air bubble
- gills
- metallic air bubble
- shiny air bubble Now, answer this question: Q: What does an underwater spider use to breathe and keep alive? A:
A:
output:
shiny air bubble