Which chemical equation is unbalanced?
1.c + o2 → co2
2.sr + o2 → 2sro
3.6h2 + 3o2 → 6h2o
4.h2 + h2 + o2 → h2o + h2o

The correct option is 2.

For a chemical equation to be balanced, the number of atoms of each element present in the reactants must be the same with that present in the products. If the number of atom of any element at any of the two side of the reaction is not the same, then the equation is not balanced. Looking at the options given above, it will be noticed that for option 2, the number of Sr atom at the reactant side is 1 while at the product side it is 2. This shows that the equation is not balanced.

i'm assuming that it's c.) red bank..

plants need sunlight, water, and carbon dioxide to make food. plants use the raw materials of water, nutrients they absorb from soil, and carbon dioxide to make sugars the plant can use. energy from the sun and chlorophyll are also needed.