Under the guidelines for triage, which of the following should be treated first
a pregnant women
a severe head injury
a broken collarbone
someone feeling nauseous

Severe head injury

Explanation:

Because pregnant women can wait, the nauseating patient can wait and a patient with broken collarbone can also wait. But the patient with severe head injury can't wait. Because of rapid blood loss and skull damage. If that patient doesn't treat on time it causes serious consequences.

halogen, any of the six nonmetallic elements that constitute group 17 (group viia) of the periodic table. the halogen elements are fluorine (f), chlorine (cl), bromine (br), iodine (i), astatine (at), and tennessine (ts).