Q: In science, what is constantly tested, sometimes revised, sometimes thrown out and sometimes well-established? A:

OPTIONS:
- a technique
- a study
- a variable
- a theory

Answer: a theory

Problem: OPTIONS:
- drains water
- pressures water
- collects water
- stores water
Q: Q: Why are the stems of many xerophytes fleshy? A:
Answer: stores water

Problem:OPTIONS:
- gravity pressure
- tidal pressure
- nitrogen pressure
- atmospheric pressure

Q: The atmosphere consists of oxygen, nitrogen, carbon dioxide, which exerts a certain pressure referred to as what? A:
****
A: atmospheric pressure

Q: What is the term for an ionic compound that produces positive hydrogen ions when dissolved in water? A:
OPTIONS:
- hydrocarbon
- sulfur
- base
- acid
acid

Q: The motion of stars in galaxies imply that there is about 10 times as much what as in the luminous objects we can see? A:
OPTIONS:
- density
- heat
- light
- mass

Answer: mass

input with options: Q: What type of metal is a good conductor of electricity? A:
OPTIONS:
- Tin
- Aluminium
- zinc
- copper
output:
copper