The apparent visual magnitude of a star is 7.3. This tells us that the star is .

(A) one of the brighter stars in the sky.
(B) not visible to the unaided eye.
(C) bright enough that it would be visible even during the day.
(D) very close to Earth.

Option (B)

Explanation:

In the field of astronomy, the magnitude scale of star is usually defined as a logarithmic scale that measures the brightness of the star, and this directly the relative distance from the earth. This magnitude value is dependent on the two main factors, namely the its brightness and the distance from a fixed point.

The given visual magnitude of a star is 7.3, and is comparatively very less brighter. This shows a relatively very large distance from the earth and due to this large distance and low luminousity, this star is not visible to our naked eye.

Thus, the correct answer is option (B).

a sonic boom is a loud boom that breaks the sound barrier

explanation:

the answer is c. the lower legs are levers, and the knees are fulcrums. the ankles hold the loads.