Which of the following operation is correct?______. A: After being treated in the bio-filter tank, the sewage is discharged overboard B: After going through the biological film, the sewage is discharged overboard C: The sewage treated in the bio-filter tank flows into the sterilization compartment D: The sewage is first collected in sterilization tank then discharged into the bio-filter tank.

The applications of nuclear radiation in agriculture mainly include ( ). A: irradiation breeding B: the storage and preservation of the food C: food sterilization D: pest control

外科手术时防止微生物进入伤口，此方法称为（）。 A: sterilization B: disinfection C: asepsisoperation D: antisepsis E: infection