Silkscreen printing is a. a technique in which an image is transferred by forcing ink through fine mesh or silk. b. a method of communication used in order to persuade the general public to consume or purchase a product or service. c. a printmaking process in which lines are cut into the surface of a plate, which is then applied with ink and pressed onto a material or paper. d. a printing medium using a stone press on which areas are made receptive to ink.

relief sculpture - images are set against a flat background.

a coin is a good example: the inscription, the date, and the figure are slightly raised above a flat surface. the ancient egyptians sometimes carved figures into a flat surface.  

pro: they take significantly less time to make and do not require as much tools or skills as free-standing

cons: not nearly as realistic, as it is not fully 3-d, and does not have the details that a free-standing one does.

freestanding sculptures (also called  carved in the round) are not attached to any  background.   they are 3-dimensional  and fully rendered.