physical science ! please help

Answer:
The answer to your question is: Synthesis
Explanation:
Synthesis In this kind of reactions, two molecules or elements combine to form a new one.
Decomposition in this reaction, one molecules form 2 or more molecules.
Single replacement in this reaction one element replaces another one of a molecule
Double replacement in this reaction there is a interchange of elements between to molecules.
Combustion in this molecules one molecule with carbon reacts with oxygen to form carbon dioxide and water.