Final answer:
Radioactive II and Radioactive III are located from people and cargo space walls by referring to radiation detectors, which can measure the emitted radiation from the radioactive substances and determine their location.
Step-by-step explanation:
Radioactive II and Radioactive III are located from people and cargo space walls by referring to radiation detectors. These detectors can measure the emitted radiation from the radioactive substances and determine their location. For example, in medical imaging, a short-lived radioactive substance called a tracer is given to a patient and an external detector is used to measure the emitted radiation. The range of the emitted y radiation is sufficient to leave the body, while the range of a and ß particles is too small for them to be observed outside the patient.