Which of the following is used to tie the arch wire into ortho brackets?

The correct choice is wire ligatures and elastomeric ligatures because these materials specifically serve the purpose of securing the arch wire into orthodontic brackets. Wire ligatures are thin strands of wire that wrap around both the bracket and the arch wire, providing a secure connection that allows for controlled movement of the teeth. Elastomeric ligatures, on the other hand, are small rubber bands that also hold the arch wire in place but can be available in various colors, adding an aesthetic element to orthodontic treatment.

The other options do not fulfill the same function. Composite resin and bonding agents are typically used to attach brackets to the teeth, not to secure the arch wire once the brackets are in position. Metal bands and separators are involved in different aspects of orthodontic treatment, such as anchoring or creating space between teeth. Lastly, screws and attachments are usually associated with anchorage and mechanical retention in orthodontic devices rather than binding the arch wire to brackets. Thus, wire ligatures and elastomeric ligatures are specifically designed for the task at hand, making them the correct answer.