Following are examples of three metamorphic rocks and a list of their uses. Marble is a metamorphic rock that is used to make floor tiles, counter tops and it is carved into statues and was used extensively in the building of the Roman Colosseum and other historic buildings. Slate is another metamâ¦.
A hex key, Allen key or Allen wrench is a tool of hexagonal cross-section used to drive bolts and screws that have a hexagonal socket in the head (internal-wrenching hexagon drive).
add a comment |. up vote 3 down vote. An API key is a unique value that is assigned to a user of this service when he's accepted as a user of the service. The service maintains all the issued keys and checks them at each request.