Cello and Double Bass
The Cello and Double Bass are the Bass (Low) instruments of the String Section of the orchestra. The Double Bass (left) is the larger of the 2 and so has a lower range. Usually the Bass player stands and the cellist sits as in the photo. All string instruments can play Pizzicato (plucked) but this is most common on the Double Bass.
Videos below include a version of "Rolling in the deep" for Cello and Piano, and an excerpt from Britten's "A young person's guide to the orchestra (Double Bass)