Do we have an obligation, as some green activists believe, to restore environmental conditions to the state which they were before human intervention?

No we don't have no obligation

Explanation:

But trust me if we don't help your town will suck and pollution will grow. So we should help but don't need to since we actually pay money for this changes even green activist pay. It is called tax.  

donald carl johanson (born june 28, 1943) is an american paleoanthropologist. he is known for discovering – with yves coppens and maurice taieb – the fossil of a female hominin australopithecine known as "lucy" in the afar triangle region of hadar, ethiopia.

hope this !

i googled "who was kolson johanson" and this is the answer i found.

sorry if this is incorrect.

opinion because one person might not like silk