Hi, You can also use the keyboard shortcut. If the Elliptical Marquee tool is invisible, press the M key. If the Rectangular Marquee is visible, you must press Shift+M to change the elliptical shape. Thanks
Very easy to find this shortcut there in PS. You just go there on tool panel and pull your mouse cursor over the tools PS will show you the shortcut with popup box... Or check this post to learn by heart... http://www.clippingpathspecialist.com/tutorial/photoshop-keyboard-shortcuts-for-mac-and-windows/