Fact 1: Oxygen is essential for cellular respiration for all aerobic organisms. Fact 2: Besides nitrogen and oxygen, the atmosphere contains many, many other molecules in trace amounts. Given the two facts above, what is essential for cellular respiration?

OPTIONS:
- Veins and arteries.
- kinetic energy
- The atmosphere
- Energy.
- heat energy
- Organic compounds
- Chemical energy
- flow of electrons

Answer: The atmosphere

Fact 1: Blood pressure is highest in arteries and lowest in veins. Fact 2: By the time blood leaves capillaries and flows into veins, pressure has decreased greatly. Given the two facts above, what happens to blood pressure after it leaves the arteries?

OPTIONS:
- Dehydration
- negative
- decreases
- movement
- sweating
- Damages them
- It expands
- heat produced

Answer: decreases

Fact 1: Dilation occurs when cell walls relax. Fact 2: Cell wall is the rigid structure that surrounds the plant cell. Given the two facts above, what happens before the rigid structure that surrounds the plant cell dilates?

OPTIONS:
- It decreases
- competition
- air cools
- relaxation
- cracking
- sweating
- rapid expansion
- It expands

Answer: relaxation

Fact 1: Adding salt to a liquid decreases the melting point of that liquid. Fact 2: Water is also a liquid. Given the two facts above, what decreases the melting point of water?

OPTIONS:
- forces
- Dilution
- erosion
- Heat energy
- chilling water
- heating water
- reading books
- adding salt

Answer:
adding salt