Why does the reading exercise require selection of both male and female soldiers, when the English is inflected only for a male soldier ?
(If we don't select החיילת אוהבת לקחת סיכונים כשהיא בצבא the exercise is marked as "incorrect")
It has to be a mistake.
The answer to this exercise is incorrect. The English regards a masculine soldier, and the Hebrew, a feminine one.
Well, I read חייל and הוא, both of which are male. (But maybe they overlooked that the English is indeed gender specific and allow both genders as answers, which would be a mistake.)
Does this sentence sounds natural : החייל אוהב לסכן כשהוא בצבא ?
No - לסכן = to puts in danger. It has to come with an object. You probably meant to use להסתכן = to take risks, to put oneself in danger.