Unlike modern versions of .NET (such as .NET Core or .NET 5+), the legacy .NET Framework used a cumulative update model for its early versions.
One of the key benefits of .NET Framework 3.5 is that it includes .NET Framework 2.0 and 3.0. This means that if you install .NET Framework 3.5, you will also have .NET Framework 2.0 and 3.0 installed on your system.