The spread of bird flu can be prevented by

(a) culling

(b) breeding

(c) burying and burning of diseased birds

When an outbreak of bird flu occurs, the affected birds should be isolated, and the carcasses of infected birds should be safely buried or burned to prevent the disease from spreading to other birds or animals. Culling involves controlled slaughter (killing) of birds within infected areas to contain the outbreak. Both culling and proper disposal methods like burying and burning are essential measures to prevent the further spread of the disease. Additionally, strict biosecurity measures in poultry farms and monitoring of wild bird populations play a crucial role in preventing and controlling the spread of bird flu.