Complex sentence: Cohen subsequently organized the Environmental Task Force, a national organization that claimed to assist local groups in their efforts to protect the environment; it published a newsletter called Re: sources, but otherwise accomplished little before it was absorbed by the more successful Environmental Action.
Split into simpler sentences: Cohen subsequently organized the Environmental Task Force, a national organization that assisted local groups in their efforts to protect the environment. The Environmental Task Force published a newsletter called Re: sources, but otherwise accomplished little before it was absorbed by the more successful Environmental Action.