Final answer:
A teacher should provide support and encouragement when a child expresses fear or anxiety, while also gently encouraging them to face their fears and try again.
Step-by-step explanation:
In order to help a child develop a positive self-concept, a teacher should provide support and encouragement when the child expresses fear or anxiety. It is important to validate the child's feelings and offer reassurance, while also gently encouraging them to face their fears and try again. For example, the teacher could say something like, "I understand that you're afraid, but I believe in you and I know you can do it. Why don't we take it slowly and try again together?" By approaching the situation with empathy and support, the teacher can help the child build confidence and develop a positive self-concept.