Complex sentence: A combination reaction is a reaction where two reactants are combined into one product.Those reaction in which two or more elements or compounds combine magnesium oxide with carbon dioxide to produce magnesium carbonate.
Split into simpler sentences: A combination reaction is a reaction where two reactants are combined into one product.Those reaction in which two or more elements or compounds combine together to form a single compound are called combination reaction. Another example is magnesium oxide combining with carbon dioxide to produce magnesium carbonate.