Solution: .col-*-pull-* changes order of the grid column, .col-*-offset-* moves columns to the right, these classes increase left margin of a column by * columns, .col-*-push-* changes order of the grid columns, .collapse indicates collapsible content.

Solution: .containerfluid is a container that spans the full width of the screen, .container is a fixed width container with widths determined by screen sites, .control-labels allows a label to be used for form validation.

Solution: .divider class is there to separate links in dropdown menu with thin horizontal border, .dl-horizontal lines up the terms 
 and descriptions 
 in 
 elements side-by-side, .dropdown creates a toggleable menu that allows user to choose one value from predefined list.

Solution: .dropdown-menu adds default styles for dropdown menu container, .dropdown-header is used to add headers inside dropdown menu, .dropdown-right right-aligns a dropdown menu, .dropdown-toggle is used on the button that should hide and show the dropdown menu.

Solution: .well adds a rounded border around an element with gray background color and some padding, .well-lg is a large well i.e. for more padding, .well-sm is a small well with less padding.

Solution: .tooltip is for the popup-box that appears when a user moves the mouse pointer over an element, .thumbnail adds a border around an element often used for images or videos to make it look like a thumbnail. .well adds a rounded border around an element with gray background color and some padding. .visible-* is used to show the content by device.

Solution: text-primary shows blue text color, .text-success shows green text color which indicates success, .text-warning shows yellow or orange text color which indicates warning, .text-muted shows grey color text, .text-danger shows red color text.

Solution: .table-condensed makes a table more compact by cutting cell padding in half, .table-hover creates a hoverable table by adding grey background color on table rows on hover, .table-responsive makes table responsive by adding the horizontal scrollbar when needed.

Solution: .tab-pane is used together with .tab-content to create toggleable or dynamic tabs or dynamic pills. .table adds basic styling to a table like bottom borders, padding etc. Cutting cell padding in half to make table more compact, .table-condensed is used. A responsive table is created by .table-responsive.

Solution: .row class is for container for responsive columns, .small creates a lighter, secondary text in any heading, .sr-only hides an element on all devices except for screen readers, .show class shows an element.