The "unless" and the "not" cancel each other out, so this should be diagrammed as IGR → (U and A). But it looks like your main issue was when it came to the next part (diagramming "Morton's book is flawed.")
By the logic of the stimulus, anything that makes the entire statement (IGR → U and A) false is sufficient for Morton's book to be flawed. The statement IGR → U and A is false when you have IGR but /U or /A, or /U and /A. So /(U or A) → F is incomplete, it should be IGR + /(U and A) → F. This is because the statement IGR → U and A is not false unless you don't have one of U or A (or neither) AND you have IGR. The stimulus already told you that you don't have U, hence having IGR without U is sufficient to conclude that Morton's book is flawed. However the stimulus did not establish whether Morton's book was IGR, which is what makes IGR necessary to conclude that Morton's book is flawed.
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The "unless" and the "not" cancel each other out, so this should be diagrammed as IGR → (U and A). But it looks like your main issue was when it came to the next part (diagramming "Morton's book is flawed.")
By the logic of the stimulus, anything that makes the entire statement (IGR → U and A) false is sufficient for Morton's book to be flawed. The statement IGR → U and A is false when you have IGR but /U or /A, or /U and /A. So /(U or A) → F is incomplete, it should be IGR + /(U and A) → F. This is because the statement IGR → U and A is not false unless you don't have one of U or A (or neither) AND you have IGR. The stimulus already told you that you don't have U, hence having IGR without U is sufficient to conclude that Morton's book is flawed. However the stimulus did not establish whether Morton's book was IGR, which is what makes IGR necessary to conclude that Morton's book is flawed.