What is the biosphere? Is it safe?

Today in my environmental science class, we learned about the biosphere. According to my research, the biosphere is the narrow layer around Earth's surface in which life can exist. The biosphere is located near Earth's surface because most of the sunlight is available near the surface. So, biosphere is like a skin of Earth. After learning this concept in my environmental science class, I started to wonder if biosphere is same as ozone. I have misunderstood that ozone layer is biosphere, however, ozone layer is stratosphere.

Many people believe that ozone layer is biosphere because they are skin of the earth. The biosphere is located near Earth's surface because most of the sunlight is available near the surface. The consequence of organism in the biosphere dies, its body is broken down and the matter in its body becomes available to other organism. By learning this concept, I have fully understood the concept of biosphere and difference between ozone layer and biosphere.