Students should write out what they mean by the terms they use. Student responses should make reference to that evidence to be completely clear. Also, students can make their explanations clearer by using examples. The four levels of competence are given to help explain each category, by contrasting exemplary written explanations to ones that need to be improved. Answer is correct and contains no extraneous or incorrect ideas.
Answer is partially correct but contains significant errors.
Answer is incorrect. Most elements of the question are answered. Only one element of the question is addressed. Answer does not address elements of the question. Answer is logical, with no contradictions.