What human activities have reduced the amount of ozone in the stratosphere

Ozone in the stratosphere helps to block ultraviolet (UV) radiation coming from the sun. UV radiation can be harmful to organisms on Earth.

a. What human activities have reduced the amount of ozone in the stratosphere? (2 points)

b. How could a reduction in stratospheric ozone affect human health? (1 point)

c. How could a reduction in stratospheric ozone affect the health of ecosystems? (1 point)

d. How have countries around the world banded together to address the problem of declining stratospheric ozone levels? (2 points)