Which of the following is a "Function" that is performed by environment?

All of the above

The environment performs four vital functions

1. It supplies resources: resources here include both renewable and non-renewable resources. Renewable resources are those which can be used without the possibility of the resource becoming depleted or exhausted. 
2. It assimilates waste
3. It sustains life by providing genetic and biodiversity
4. It also provides aesthetic services like scenery etc.