The elements listed in the choices are radioactive materials. These materials are very unstable because of the high neutron-to-proton ratio in the nucleus. Because of this, they spontaneously undergo nuclear reactions by giving off sub-particles in order to lower the ratio. They emit radiation in the form of alpha, beta or gamma.
Half-life is the length of time it needs to completely react half of the original amount. For example, it would take Bismuth 60.5 seconds to use up half of its amount. Therefore, the lower the half-life the faster the reaction is and the lesser the residual amount will be. With that being said, the answer would be Bismuth because it only takes seconds.
Answer:
Planning
Explanation:
The Planning section chief is needed to develop and organize an incident action plan for the large events. He is one responsible for preparing the incident action plans. He also manages the information as well as maintains the situational awareness for the incident to take place.
He is in control of the overall execution of the event.
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I think this question is meant to be placed in the Geometry category. :)
Maps have a legend at the bottom of the map that tells you what each symbol means. The other things are not seen on a map.
