Final answer:
The primary route of transmission for influenza is through airborne droplets from coughing.
Step-by-step explanation:
The primary route of transmission for influenza is through airborne droplets from coughing. When an infected person coughs or sneezes, they expel droplets containing the influenza virus into the air. These droplets can be inhaled by nearby individuals, allowing the virus to enter their respiratory system and infect them.