The formation of depletion layer of ozone is due to human made ODS. They react with the ozone layer and then deplete it.
The depletion could be reduced by curing CFC's. They cause damage to the ozone.
The main disadvantage is the UV entering the earth. It causes various fatal problems.
There are steps to preserve Depletion of ozone. Planting trees, using HCFC's, avoiding dumping etc.
deplation of forest cover
The chemical mainly responsible for ozone deplation are CFC's. They contain chlorine and fluorine which react with ozone to destroy it.
If your question is 'Is the trophoblast present during germ layer formation (i.e. gastrulation) ?' then the answer is YES
The formation of the ozone layer
UV rays formed the ozone layer. They also destroyed the ozone.
Ozone has nothing to contribute in cloud formation. It is all done in the troposphere layer.
Ozone layer absorbs the UV rays of the sun. They are fatal for life on earth.
Stratus corneum
The formation of the ozone layer