Taxis response is to move towards or away from the stimulus. If the organism moves towards the stimulus the taxis is positive, while if it moves away the taxis is negative. For example, flagellate protozoans of the genus "Euglena" move towards a light source. This reaction or behaviour is called "positive phototaxis", since phototaxis refers to a response to light and the organism is moving towards the stimulus. Many types of taxis have been identified, including: Depending on the type of sensory organs present, a taxis can be classified as a "klinotaxis", where an organism continuously samples the environment to determine
Yellow-Top taxis Yellow-Top taxis were the Mercedes Benz 220S Ponton, followed by the Austin Cambridge A60. In the 1970s the Cambridge A60 still continued until the early 1980s followed by the Opel Rekord D, Peugeot 504, Morris Marina and the Russian GAZ Volga 24. The static Nissan Cedric and Toyota Crown has been there for decades from 1980s. The Nissan Cedric taxis were scrapped in 2008 and Toyota Crown taxis were scrapped in 2012. Yellow-Top taxis Yellow-Top taxis are a collective group of individually owned taxis in Singapore. The name is derived from their yellow top and black body. The "Singapore Taxi