I want to get the icons behind the top icon, how can I get them visible? I am using Macbook Air without a mouse.
Unlike Photoshop, you don't need any special keys to access the hidden tools.
All you need to do is click and hold. If you click, hold and move to the right slightly the tools tend to pop up a bit faster.
Photoshop uses the Control plus a click to access hidden tools. Illustrator doesn't do this. Even if you want it to.