While working with particles, what does velocity control?

What happens to the presets which are tied to a parameter when you duplicate it?

In a Standard preview (without rendering a RAM preview) After Effects will render each frame as fast as it can – which usually means playing them much _______ than the comp’s frame rate.

You can only create a mask by using the pen tool or the rectangle tool?

What is the keyboard shorcut for redo?

The Unsharp Mask effect will blur the image.