1. What characters are used to echo a string with the ability to extrapolate variable values?

2. What characters are used to echo a string literally, without extrapolation?

3.When commenting, the php parsing agent ignores how much of the code when using two forward slashes? ( // )

The foward slashes (//) is used to comment out all the code up until someone puts up the foward slashes again (//) The foward slashes are normaly used for comments and also for reminders about the different sections of the code. Almost like breadcrumbs.

4. When commenting, the php parsing agent ignores how much of the code when using forward slash asteriskÖasterisk forward slash (/* */)?

This will completely WHIPE OUT THE CODE!!!!! This is more used with having to check the code and figuring out why certain parts did not work. The way to stop having the code whiped out is by adding the /**/ again. Which will focus on a certain part of the code.