What is the primary difference between a fuel cell and a battery?
A) Fuel cells do not run down because they can be refueled; batteries run down and need to be recharged.
B) Batteries can be recharged, fuel cells cannot.
C) Batteries supply electricity; fuel cells supply heat.
D) Fuel cells oxidize to supply electricity, batteries reduce to supply electricity.
E) Fuel cells do not use metals as oxidants and reductants, batteries have a static reservoir of oxidant and reductant.
Question 2
The use of tractors and other heavy farm machinery compacts soil. How might this compacting affect soil fertility?
A) The soil fertility is harmed because the weight of the heavy machinery squeezes out the water.
B) The increased pressure causes fertilizer molecules to react with one another, which has the effect of harming soil fertility.
C) Once compacted the soil is not able to hold water and air, which harms the fertility.
D) The weight of the heavy machinery kills decomposers, such as worms, which has the effect of harming soil fertility.