a.) Testing and Debugging
Testing is process of verifying if the application matches requirements and reporting bugs; Testing is usually done by an independent testing team while debugging is a process of finding and fixing bugs with the intention of reducing bugs; Debugging is usually done by the programmer.
b.) Two tier and Three tier architecture
In a two tier architecture there is a data server and a client application. Client application directly accesses the server data. In a three tier architecture there is a data server, a client application and a server application. Client application calls the server application which in turn fetches data from the data server and returns back to client application.
c.) Alpha testing and Beta testing
Alpha testing is conducting acceptance testing in the environment where the application was developed. It is done by the customer. Beta testing is conducting acceptance testing is the customer environment. It is done by the group of customers or users who will actually be using it.
d.) Static testing and dynamic testing
Static testing is checking the application without actually running the application whereas dynamic testing checks the application by running it.