The environment modified by human activities is called

1. A

   Natural environment

   Natural environment is the biophysical setting little modified by people. The question asks for the environment modified by human activities, so this is the opposite term.

2. B

   Anthropogenic environment

   Anthropogenic environment means the environment shaped or created by human action (from Greek anthropos, human). Cities, farms, mines and pollution regimes are anthropogenic. That is the official key.

3. C

   Urban environment

   Urban environment is only one subset of human-modified settings. Villages, dams and plantations are anthropogenic without being urban. The option is too narrow.

4. D

   Modem environment

   ‘Modern environment’ is not the technical term used in this pairing. Modernity is not the definition of human-modified nature.

Summary. Official key is (b) anthropogenic environment. It is the standard label for nature altered by human activity. Urban is a subset; natural is the contrast; ‘modern’ is not the term.