You are presented with the quiz "What is essential for cellular respiration?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "oxygen is essential for cellular respiration for all aerobic organisms" and "besides nitrogen and oxygen, the atmosphere contains many, many other molecules in trace amounts". So, what's the best answer to the question?

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

Answer: The atmosphere

You are presented with the quiz "What happens to blood pressure after it leaves the arteries?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "blood pressure is highest in arteries and lowest in veins" and "by the time blood leaves capillaries and flows into veins, pressure has decreased greatly". So, what's the best answer to the question?

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

Answer: decreases

You are presented with the quiz "What happens before the rigid structure that surrounds the plant cell dilates?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "dilation occurs when cell walls relax" and "cell wall is the rigid structure that surrounds the plant cell". So, what's the best answer to the question?

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

Answer: relaxation

You are presented with the quiz "What decreases the melting point of water?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "adding salt to a liquid decreases the melting point of that liquid" and "water is also a liquid". So, what's the best answer to the question?

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

Answer:
adding salt