The stratosphere contains the ozone layer, which is a region of high ozone concentration. Ozone is a molecule composed of three oxygen atoms, and it absorbs UV radiation from the sun, preventing it from reaching the Earth's surface.

Human activities, particularly the release of chlorofluorocarbons (CFCs) and other ozone-depleting substances, are the primary cause of ozone depletion in the stratosphere. CFCs are chemicals that were widely used in refrigeration, air conditioning, and aerosol products before their harmful effects on the ozone layer were discovered.

CFCs release chlorine atoms when they are exposed to UV radiation in the stratosphere. These chlorine atoms then react with ozone molecules, destroying them and leading to ozone depletion.

The Montreal Protocol is an international agreement that was signed in 1987 to phase out the production and use of ozone-depleting substances, including CFCs. The protocol has been successful in reducing the levels of ozone-depleting substances in the atmosphere, and it has helped to slow down the rate of ozone depletion.

Ozone depletion leads to increased UV radiation reaching the Earth's surface, which can have a number of harmful consequences, including higher rates of skin cancer and cataracts in humans, damage to crops and forests, and disruption of marine ecosystems.

The ozone layer is still depleted, but the rate of depletion has slowed down significantly since the implementation of the Montreal Protocol. The ozone layer is expected to fully recover by the middle of this century.

Individuals can help protect the ozone layer by reducing their use of products that contain ozone-depleting substances, choosing products that are labeled 'ozone-friendly', supporting policies that promote the use of renewable energy sources, and educating themselves and others about the importance of protecting the ozone layer.

The stratosphere provides the necessary conditions for the production of ozone, contains the precursors for ozone formation, and shields the ozone layer from harmful radiation.

The chemical reaction that leads to the formation of ozone in the stratosphere is O + O_2 → O_3.

The ozone layer absorbs harmful UV radiation from the sun, protecting life on Earth from its harmful effects.

The release of chlorofluorocarbons (CFCs) and other ozone-depleting substances is the main human activity that contributes to ozone depletion.

The Montreal Protocol is an international agreement to phase out the production and use of ozone-depleting substances.

Ozone depletion can lead to increased risk of skin cancer and cataracts, damage to crops and forests, and disruption of marine ecosystems.

Reducing the use of products that contain ozone-depleting substances, promoting the use of renewable energy sources, and implementing policies that encourage the phase-out of ozone-depleting substances are all measures that can be taken to protect the ozone layer.

The ozone layer is still depleted, but the rate of depletion has slowed down due to the implementation of the Montreal Protocol.