Teacher:Given a text passage, you need to generate a suitable title as the output. The output title should be one of the words/phrases used in the passage and must be no longer than five words. 
Teacher: Now, understand the problem? Solve this instance: Paragraph:    The plain maskray generally hunts at the surface of the bottom substrate , rather than digging for prey . Its diet consists predominantly of caridean shrimp and polychaete worms . Small bony fishes are also eaten , along with the occasional penaeid prawn or amphipod . Larger rays consume a greater variety of prey and relatively more polychaete worms when compared to smaller rays . This species is parasitized by the tapeworm Acanthobothrium jonesi . 
 Like other stingrays , the plain maskray is viviparous with the developing embryos sustained to term by histotroph ( " uterine milk " ) produced by the mother . Mature females have a single functional ovary and uterus , on the left . Litter size is one or two ; the newborns measure 12 – 14 cm ( 4 @.@ 7 – 5 @.@ 5 in ) across . Males and females reach sexual maturity at disc widths of 20 – 21 cm ( 7 @.@ 9 – 8 @.@ 3 in ) and 18 – 19 cm ( 7 @.@ 1 – 7 @.@ 5 in ) respectively . The maximum lifespan is estimated to be 9 years for males and 13 years for females .   Question: what is the suitable title of the passage ?
Student:
 Biology and ecology