Problem: OPTIONS:
- oil rain
- ozone rain
- dioxide rain
- acid rain
Q: Q: Calcium hydroxide and calcium carbonate are effective in neutralizing the effects of what on lakes? A:
Answer: acid rain

Problem:OPTIONS:
- rayon
- styrofoam
- silicon
- rubber

Q: What is polyisoprene better known as? A:
****
A: rubber

Q: Before the atmosphere became oxygenated, the planet was subjected to what harmful energy source, meaning the first organisms would have flourished where they were more protected? A:
OPTIONS:
- evaporation
- conduction
- convection
- radiation
radiation

Q: What is the most abundant living thing on earth that can be found in almost any environment? A:
OPTIONS:
- pests
- viruses
- pathogens
- bacteria

Answer: bacteria

Question: Q: What serves to replace nonreproducing specialized cells as needed in the adult body? A:
OPTIONS:
- osteoclast cells
- monocyte cells
- dendritic cells
- stem cells
Answer: stem cells

input: OPTIONS:
- hypothesis
- theory
- notion
- principle Now, answer this question: Q: A _______ of biology is a fundamental concept that is just as true for a bee or a sunflower as it is for us. A:
A:
output:
principle