Answer to Question 1
Reuse is not limited to one aspect of the development or the product. Components are the most reliable and effective mechanism for reuse since they provide black boxes that can be assembled with no change. Patterns encapsulate experience in solving problems and, consequently, can be labeled as experience reuse. Inheritance is a specifically object-oriented technology that allows the descendants of a class to reuse its behavior, with or without modifications. Web services can be described as components on the Web: they provide services across the Internet or intranets and consumers can ignore how the services are rendered. The aim of methodology is to reuse abstract ideas as guidelines for discovering solutions on your own. Refactoring is the consolidation of analysis, design or implementation artifacts to eliminate useless redundancy. Source code reuse is usually discouraged but can be valuable in providing examples for learning. Finally, development frameworks provide templates bare skeletons that can be expanded into full solutions.
Answer to Question 2
Problem space is the context from which the problem originates and in which the solution must operate. Also called problem domain.
