Answer 1

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The .NET framework is a software development framework from Microsoft. It provides a controlled programming environment where software can be developed, installed and executed on Windows-based operating systems. 
The principal design features are:
Interoperability: This allows for .NET-developed programs to access functionalities in programs developed outside .NET.
Common Runtime Engine: Also known as the common language runtime, this allows programs developed in .NET to exhibit common behaviors in memory usage, exception handling and security.
Language Independence: Common language infrastructure specifications (CLI) allow for the exchange of data types between two programs developed in different languages.
Base Class Library: A library of code for most common functions--used by programmers to avoid repetitive rewriting of code.
Ease of Deployment: There are tools to ensure the ease of installing programs without interfering with previously installed applications.
Security: Programs developed in .NET are based on a common security model.