LinearLayout : A layout that organizes its children into a single horizontal or vertical row. It creates a scrollbar if the length of the window exceeds the length of the screen.It means you can align views one by one (vertically/ horizontally).
RelativeLayout : This enables you to specify the location of child objects relative to each other (child A to the left of child B) or to the parent (aligned to the top of the parent). It is based on relation of views from its parents and other views.
WebView : to load html, static or dynamic pages.
For more information refer this link:http://developer.android.com/guide/topics/ui/layout-objects.html