Answer:
1) Oxygen
2) Carbonation
3) Water reacting chemically with minerals in rock
4) A tropical region that is hot and humid all year long
Explanation:
1) Iron rust is formed when iron comes into contact water where there is oxygen present. The process of iron rusting occurs more quickly in the presence of ions from salt, due to the enabling electrochemical reactions
2) When carbonation of rain water occurs by the mixing of rain water with atmospheric carbon dioxide, and the solution enters the soil, the weak acid formed dissolve the limestone with the capability to forms caves depending on the location conditions
3) Hydrolysis is a term used to describe a reaction wit water
4) Chemical weathering is the weakening of minerals and rocks by rain water chemicals which will be supported in the hot and humid weather condition that last all year long in the tropics.