Problem: OPTIONS:
- gel
- gas
- liqued
- solid
Q: Q: In what state of matter is butter at room temperature? A:
Answer: solid

Problem:OPTIONS:
- asexual
- symbiotic
- prokaryotic
- allopatric

Q: What type of speciation occurs when groups from the same species are geographically isolated for long periods? A:
****
A: allopatric

Q: What is the type of plant called when its leaves seasonally turn color and fall off? A:
OPTIONS:
- conifer
- verdant plant
- evergreen
- deciduous plant
deciduous plant

Q: Models may be physical, conceptual, or what else? A:
OPTIONS:
- experimental
- fundamental
- theoretical
- mathematical

Answer: mathematical

Question: Q: Like the strings of cello, anything that vibrates produces waves of what? A:
OPTIONS:
- heating
- light
- sound
- energy
Answer: energy

input: OPTIONS:
- Chernobyl disaster
- coal industry boom
- second world war
- industrial revolution Now, answer this question: Q: During what time period did poor air quality become a problem? A:
A:
output:
industrial revolution