What can a person do to limit exposure to X-rays?

To limits exposure of X-rays, One can do the following things:

1) Use a  protective shield through which X-Rays can't pass.

2) Prevent X-rays as much as u can.

3) Don't go to places where you doubt the presence of X-Ray Radiations.

4) If not needed, Don't do CT scan.

correct answer is option a.

tropopause, stratopause and mesopause have all in common aspect that is point of maximum temperature in its layer of the atmosphere. all layers of atmosphere observe abrupt change in temperature. tropopause is the boundary between troposphere and stratosphere. stratopause is the boundary between stratosphere and mesosphere. mesopause is the boundary between mesosphere and thermosphere. these all boundaries are ranges between altitude of 0 to 80 km.

a time line cause it goes from 685 to 978