Which statement justifies (0<\sqrt{0.49}<1) on the number line?

Correct answer: Because (0<0.49<1)

The governing property is that for a non-negative number a, if 0<a<1, then its principal square root also satisfies 0<\sqrt{a}<1. Here 0<0.49<1, so taking the non-negative square root gives 0<\sqrt{0.49}<1. In fact, \sqrt{0.49}=0.7, which directly confirms the statement. Therefore option A is correct. Option B contradicts the given value, option C confuses the square root with the number 49, and option D is impossible because a principal square root is never negative. The interval property, rather than an unsupported approximation, provides the justification.