Question

the main responsibility of the transportation security administration is to
provide police protection for airline passengers
maintain secure flight schedules for the airlines
make sure planes are mechanically ready for flying.
screen passengers for weapons and explosives

Explanation:

The Transportation Security Administration (TSA) focuses on passenger - screening to prevent weapons and explosives from getting on planes. It is not responsible for police protection, flight - schedule security, or aircraft mechanical readiness.

Answer:

screen passengers for weapons and explosives