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The hypothesis that plant growth and development is coordinated by plant hormones or plant growth regulators first emerged in the late 19th century. Darwin experimented on the movements of plant shoots and roots towards light and gravity, and concluded "It is hardly an exaggeration to say that the tip of the radicle . . acts like the brain of one of the lower animals . . directing the several movements". About the same time, the role of auxins (from the Greek auxein, to grow) in control of plant growth was first outlined by the Dutch scientist Frits Went. The first known auxin, indole-3-acetic acid (IAA), which promotes cell growth, was only isolated from plants about 50 years later. This compound mediates the tropic responses of shoots and roots towards light and gravity. The finding in 1939 that plant callus could be maintained in culture containing IAA, followed by the observation in 1947 that it could be induced to form roots and shoots by controlling the concentration of growth hormones were key steps in the development of plant biotechnology and genetic modification.

What can plant callus be coaxed into doing?
Answer: form roots and shoots
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Due to a complete estrangement between the two as a result of campaigning, Truman and Eisenhower had minimal discussions about the transition of administrations. After selecting his budget director, Joseph M. Dodge, Eisenhower asked Herbert Brownell and Lucius Clay to make recommendations for his cabinet appointments. He accepted their recommendations without exception; they included John Foster Dulles and George M. Humphrey with whom he developed his closest relationships, and one woman, Oveta Culp Hobby. Eisenhower's cabinet, consisting of several corporate executives and one labor leader, was dubbed by one journalist, "Eight millionaires and a plumber." The cabinet was notable for its lack of personal friends, office seekers, or experienced government administrators. He also upgraded the role of the National Security Council in planning all phases of the Cold War.

Along with George Humphrey, what cabinet official did Eisenhower have a close relationship with?
Answer: John Foster Dulles
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The language of treaties, like that of any law or contract, must be interpreted when the wording does not seem clear or it is not immediately apparent how it should be applied in a perhaps unforeseen circumstance. The Vienna Convention states that treaties are to be interpreted "in good faith" according to the "ordinary meaning given to the terms of the treaty in their context and in the light of its object and purpose." International legal experts also often invoke the 'principle of maximum effectiveness,' which interprets treaty language as having the fullest force and effect possible to establish obligations between the parties.

Besides unclear language what might also arise that necessitates the interpretation of the language of a treaty?
Answer:
a perhaps unforeseen circumstance