How do your arm muscles work to lift a mug of coffee to your lips?

1.the biceps muscle contracts while the triceps muscle relaxes. only then can the forearm move up to lift the mug.
2.the muscle tendons in your arms stretch to their limit as a result of the flexibility exercises that lift the mug.
3.your muscles rapidly increase the speed at which they twitch to trigger your arm movement.
4.your biceps and triceps muscles first relax, and then the arm muscle raises the mug.

What is the style of discipline in which the teacher or parent establishes rules, monitors the child's behavior, then enforced rules by administering appropriate punishment

What should be changed to make the following sentence true? "the stress model suggests that people with a predisposition for a disorder are more likely to develop the disorder when faced with stress."

You isolate an infectious substance capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus, viroid, or prion. you have four methods at your disposal to analyze the substance and determine the nature of the infectious agent.i. treat the substance with enzymes that destroy all nucleic acids and then determine whether the substance is still infectious.ii. microscope.iii. culture the substance on nutritive medium, away from any plant cells.iv. treat the sample with proteases that digest all proteins and then determining whether the substance is still infectious.if you already know that the infectious agent was either bacterial or viral, which method(s) listed above would allow you to distinguish between these two possibilities? a) ib) iic) ii or iiid) iv