A synthesis reaction or direct combination reaction is one of the most common types of chemical reactions. In a synthesis reaction two or more chemical species combine to form a more complex product.
A design review is a milestone within a product development process whereby a design is evaluated against its requirements in order to verify the outcomes of previous activities and identify issues before committing to-and if need to be re-prioritise-further work.
The number of reviews is dependent on the complexity of the design. A single review may be appropriate at the conclusion of the design project for a simple design or a minor change to an existing product. Multiple reviews are typically conducted for projects involving subsystems or complex designs.