Please choose the correct ending to complete the given sentence: Health: [header] How to test iodine levels [title] Purchase a tincture of iodine. [step] If you don't already have an iodine solution at home, you will need to purchase a tincture of iodine. These are available at most pharmacies and drug stores, as well as online.

Ending1: Iodine is an amino acid that acts like a residremic acid. [substeps] Iodine is known as bromelain and isotretinoin. Ending2: Make sure that the tincture you purchase is fresh and cold; otherwise, it may act as a foul-tasting additive that can irritate the patient's throat. [substeps] Iodine works by boosting the immune system. Ending3: You will need three ounces (23 g) of iodine per pound (89 g) per kilogram of body weight. [substeps] Iodine is found naturally in many different little bases. Ending4: [substeps] While most iodine solutions have an orange tint, some are clear. Be sure to buy an orange solution so that it shows up on your skin.

Answer format: ending1/ending2/ending3/ending4