combining sentences pt.2

1.) The snowmobile roared through the trees, plowed through the brush, and disappeared into the wilderness.
2.)You are at the hear of this city, when you are the heart of Nature.
3.)The President was not a stupid man, but the intricacies of government bored him, and the dirty work of politics repelled him.
4.)The alien creature was lost, alone on earth, afraid of humans, lonely, and looking for its companions
5.) Darling trotted back, smiling, breathing deeply but easily, feeling wonderful, not tired, although this was the tail end of practice, and he'd run eighty yards