Problem: Athens retained its position as the most prestigious seat of higher education, especially in the domains of philosophy and rhetoric, with considerable libraries and philosophical schools. Alexandria had the monumental Museum (i.e. research center) and Library of Alexandria which was estimated to have had 700,000 volumes. The city of Pergamon also had a large library and became a major center of book production. The island of Rhodes had a library and also boasted a famous finishing school for politics and diplomacy. Libraries were also present in Antioch, Pella, and Kos. Cicero was educated in Athens and Mark Antony in Rhodes. Antioch was founded as a metropolis and center of Greek learning which retained its status into the era of Christianity. Seleucia replaced Babylon as the metropolis of the lower Tigris.
What library was estimated to have 700,000 volumes?
The answer is the following: Library of Alexandria

Problem: London's buildings are too diverse to be characterised by any particular architectural style, partly because of their varying ages. Many grand houses and public buildings, such as the National Gallery, are constructed from Portland stone. Some areas of the city, particularly those just west of the centre, are characterised by white stucco or whitewashed buildings. Few structures in central London pre-date the Great Fire of 1666, these being a few trace Roman remains, the Tower of London and a few scattered Tudor survivors in the City. Further out is, for example, the Tudor period Hampton Court Palace, England's oldest surviving Tudor palace, built by Cardinal Thomas Wolsey c.1515.
What, in part, is the reason for London's lack of a singularly characteristic architectural style among its buildings?
The answer is the following: their varying ages

Problem: In 1954, Eisenhower articulated the domino theory in his outlook towards communism in Southeast Asia and also in Central America. He believed that if the communists were allowed to prevail in Vietnam, this would cause a succession of countries to fall to communism, from Laos through Malaysia and Indonesia ultimately to India. Likewise, the fall of Guatemala would end with the fall of neighboring Mexico. That year the loss of North Vietnam to the communists and the rejection of his proposed European Defence Community (EDC) were serious defeats, but he remained optimistic in his opposition to the spread of communism, saying "Long faces don't win wars". As he had threatened the French in their rejection of EDC, he afterwards moved to restore West Germany, as a full NATO partner.
What country did Eisenhower believe communists would conquer if they took over Guatemala?
The answer is the following: Mexico

Problem: While the majority of flowers are perfect or hermaphrodite (having both pollen and ovule producing parts in the same flower structure), flowering plants have developed numerous morphological and physiological mechanisms to reduce or prevent self-fertilization. Heteromorphic flowers have short carpels and long stamens, or vice versa, so animal pollinators cannot easily transfer pollen to the pistil (receptive part of the carpel). Homomorphic flowers may employ a biochemical (physiological) mechanism called self-incompatibility to discriminate between self and non-self pollen grains. In other species, the male and female parts are morphologically separated, developing on different flowers.
How are some male and female parts separated for some species?
The answer is the following:
different flowers