Based on the clue 'add this letter to moral it becomes fatal', what is the answer?

Based on the clue 'add this letter to jupiters moon io you get an ac...', what is the answer? Based on the clue 'add this letter to lack to get what a taut rope la...', what is the answer? Based on the clue 'add this letter to make ink red or at least a shad...', what is the answer? Based on the clue 'add this letter to mars you get a fen', what is the answer? Based on the clue 'add this letter to plant it becomes easily bent', what is the answer? Based on the clue 'add this letter to rave youre in deep trouble as ...', what is the answer? Based on the clue 'add this letter to rim it becomes the rim of a ha...', what is the answer? Based on the clue 'add this letter to rook to get someone who might r...', what is the answer?