Final answer:
The stratosphere contains protective ozone, while tropospheric ozone is harmful to organisms.
Step-by-step explanation:
The correct answer is d. stratosphere; troposphere.
Ozone in the stratosphere acts as a shield protecting Earth's surface from UV radiation. The ozone layer in the stratosphere absorbs a portion of the radiation from the sun, preventing it from reaching the planet's surface.
On the other hand, ozone in the troposphere is harmful to organisms. It is a component of smog and can cause health problems.