The Oyster card is a form of electronic ticket used on public transport in Greater London in the United Kingdom.It is promoted by Transport for London and is valid on travel modes across London including London Underground, London Buses, the Docklands Light Railway (DLR), London Overground, Tramlink, some river boat services, and most National Rail services within the London fare zones.Finally there was a glimpse of a modern geographical map of the tube network I hadn’t seen before.Dating from the early 1970s, it shows the network and its actual relation with the rest of London, and can be compared with the more modern London Connections map.Illustrated vignettes, positioned near their actual location, show the houses and scenes. The Corporate Archives division of Transport for London recently held a short internal exhibition at their headquarters at Palestra, called “Mapping London” and showcasing new and old maps of London’s transport from the archive.
and "Oyster" was chosen as a fresh approach that was not directly linked to transport, ticketing or London. According to Andrew Mc Crum, now of Appella brand name consultants, who was brought in to find a name by Saatchi and Saatchi Design (contracted by Tran Sys), Oyster was conceived and promoted because of the metaphorical implications of security and value in the component meanings of the hard bivalve shell and the concealed pearl, the association of London and the River Thames with oysters, and the well-known travel-related idiom "the world is your oyster".
Sponges are similar to other animals in that they are multicellular, heterotrophic, lack cell walls and produce sperm cells.
Unlike other animals, they lack true tissues and organs, and have no body symmetry.
Sponges do not have nervous, digestive or circulatory systems.
Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes.