Problem: In 1896, Eugen Baumann observed iodine in thyroid glands. In 1897, Christiaan Eijkman worked with natives of Java, who also suffered from beriberi. Eijkman observed that chickens fed the native diet of white rice developed the symptoms of beriberi but remained healthy when fed unprocessed brown rice with the outer bran intact. Eijkman cured the natives by feeding them brown rice, discovering that food can cure disease. Over two decades later, nutritionists learned that the outer rice bran contains vitamin B1, also known as thiamine.
What element can be found in thyroid glands?
The answer is the following: iodine

Problem: The risk of reactivation increases with immunosuppression, such as that caused by infection with HIV. In people coinfected with M. tuberculosis and HIV, the risk of reactivation increases to 10% per year. Studies using DNA fingerprinting of M. tuberculosis strains have shown reinfection contributes more substantially to recurrent TB than previously thought, with estimates that it might account for more than 50% of reactivated cases in areas where TB is common. The chance of death from a case of tuberculosis is about 4% as of 2008, down from 8% in 1995.
In what year did the risk of dying from TB reach half what it was in 1995?
The answer is the following: 2008

Problem: While Brazil was fighting the US through the WTO's Dispute Settlement Mechanism against a heavily subsidized cotton industry, a group of four least-developed African countries – Benin, Burkina Faso, Chad, and Mali – also known as "Cotton-4" have been the leading protagonist for the reduction of US cotton subsidies through negotiations. The four introduced a "Sectoral Initiative in Favour of Cotton", presented by Burkina Faso's President Blaise Compaoré during the Trade Negotiations Committee on 10 June 2003.
What has the Cotton-4 been in regards to the US cotton subsidies?
The answer is the following: leading protagonist

Problem: It is also stated that Hera kidnapped Eileithyia, the goddess of childbirth, to prevent Leto from going into labor. The other gods tricked Hera into letting her go by offering her a necklace, nine yards (8 m) long, of amber. Mythographers agree that Artemis was born first and then assisted with the birth of Apollo, or that Artemis was born one day before Apollo, on the island of Ortygia and that she helped Leto cross the sea to Delos the next day to give birth to Apollo. Apollo was born on the seventh day (ἑβδομαγενής, hebdomagenes) of the month Thargelion —according to Delian tradition—or of the month Bysios—according to Delphian tradition. The seventh and twentieth, the days of the new and full moon, were ever afterwards held sacred to him.
What was the necklace made of?
The answer is the following:
amber