Which element(s) are not balanced in this equation?

fe2o3 + 3 co → fe + 3 co2

a.
only the fe is unbalanced.

b.
only the o is unbalanced

c.
fe and o are both unbalanced.

d.
c and o are both unbalanced

pure water does not conduct electricity very well. however, when certain substances are dissolved in water, the solution does conduct electricity. you can make a simple device that shows how well a solution conducts electricity. this device uses a flashlight bulb to indicate how well the solution conducts electricity. the better the solution conducts electricity, the brighter the bulb will glow.

explanation:

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.