2D Drawing Representation - General Questions

This is a rounded exterior blend between surfaces:

This is a hollow cylinder that is often used as a protective sleeve or guide or as a bearing:

This is a flat or rounded tab protruding from a surface, usually to provide a method for attachment:

These are used to attach parts to a cylinder so they won't turn on it:

This is an angled surface used on cylinders to make them easier to handle:

This is a conical-shaped recess around a hole, often used to receive a tapered screw head: