Solution: .list-unstyled removes default list-style and left margin on list items, it works on both 
 and 
, this class only applies to immediate children list items to remove the default list-style from any nested lists, can be applied to any listed lists as well. .initialism displays text inside  tag. All items in a single line is displayed by .list-inline.

Solution: .dl-horizontal lines up the terms and descriptions in 
 element side-by-side, it starts off like default 
s, but when browser window expands it will line up side-by-side. .list-unstyled removes default list-style and left margin on list items. .initialism displays text inside  tag.

Solution: .lead makes a text stand out, .small indicates smaller text, set to 85% of the size of the parent, .text-left indicates left-aligned text, .text-center indicates center-aligned text.

Solution: .caret indicates dropdown functionality, it will reverse automatically in dropup menus, .close indicates a close icon, .sr-only hides an element to all devices except screen readers. .text-hide hides the text present in document.

Solution: .divider separates items inside dropdown menu with horizontal line, .disabled disables an item in dropdown menu, .collapse indicates collapsible content which can be hidden or shown on demand. .dropdown-header class add header inside dropdown menu.

Solution: collapse.in shows collapsible content by default, .panel-collapse shows collapsible panel, toggle between hiding and showing panel, .collapse indicates collapsible content which can be hidden or shown on demand. .dropdown-header class add header inside dropdown menu.

Solution: .navbar-toggle styles button that should open navbar on small screens, often used together with three .icon-bar classes to indicate a toggleable menu icon, .navbar-text vertical align any elements inside navbar that are not links. Left, top and right borders from the nav bar can be removed by .navbar-static-top. Alignment of nav links, text and buttons in the nav bar to the right can be done by .navbar-right.

Solution: .navbar-nav is used on 
 container that contains list items with links inside a navigation bar, .navbar-right aligns nav links, forms, buttons or text in navbar to the right. Left, top and right borders from the nav bar can be removed by .navbar-static-top. .navbar-toggle styles button that should open navbar on small screens.

Solution: .navbar-nav is used on 
 container that contains list items with links inside a navigation bar. .navbar-right aligns nav links, forms, buttons or text in navbar to the right. .navbar-static-top removes left, top and right borders (rounded corners) from navbar, default navbar has a grey border and 4px border-radius by default, .navbar-toggle styles button that should open navbar on small screens.

Solution: .previous aligns .pager previous button to the left, .next aligns .pager next button to the right, .disabled indicates unclickable link, .pager provides simple pagination links (next/previous).