What are the differences between hammer curls and cross body curls, and which exercise is more effective for targeting the biceps?

Hammer curls involve holding the dumbbells with a neutral grip, while cross body curls involve bringing the dumbbell across the body. Both exercises target the biceps, but hammer curls also engage the brachialis muscle. Hammer curls are generally more effective for overall bicep development, while cross body curls can help target specific areas of the biceps.