Problem: The inflection of determinatives is complex, specially because of the high number of elisions, but is similar to the neighboring languages. Catalan has more contractions of preposition + article than Spanish, like dels ("of + the [plural]"), but not as many as Italian (which has sul, col, nel, etc.).
What type of word is added to the contraction of the preposition?
The answer is the following: article

Problem: Mammals include the largest animals on the planet, the rorquals and other large whales, as well as some of the most intelligent, such as elephants, primates, including humans, and cetaceans. The basic body type is a four-legged land-borne animal, but some mammals are adapted for life at sea, in the air, in trees, or on two legs. The largest group of mammals, the placentals, have a placenta, which enables feeding the fetus during gestation. Mammals range in size from the 30–40 mm (1.2–1.6 in) bumblebee bat to the 33-meter (108 ft) blue whale.
Which four legged mammal is considered to be the smartest?
The answer is the following: elephants

Problem: The May Fourth Movement helped to rekindle the then-fading cause of republican revolution. In 1917 Sun Yat-sen had become commander-in-chief of a rival military government in Guangzhou in collaboration with southern warlords. Sun's efforts to obtain aid from the Western democracies were ignored, however, and in 1920 he turned to the Soviet Union, which had recently achieved its own revolution. The Soviets sought to befriend the Chinese revolutionists by offering scathing attacks on Western imperialism. But for political expediency, the Soviet leadership initiated a dual policy of support for both Sun and the newly established Chinese Communist Party (CCP).
How did the Soviets try to befriend  the Chinese Revolutionist?
The answer is the following: by offering scathing attacks on Western imperialism.

Problem: In most bacteria, a cell wall is present on the outside of the cell membrane. The cell membrane and cell wall comprise the cell envelope. A common bacterial cell wall material is peptidoglycan (called "murein" in older sources), which is made from polysaccharide chains cross-linked by peptides containing D-amino acids. Bacterial cell walls are different from the cell walls of plants and fungi, which are made of cellulose and chitin, respectively. The cell wall of bacteria is also distinct from that of Archaea, which do not contain peptidoglycan. The cell wall is essential to the survival of many bacteria, and the antibiotic penicillin is able to kill bacteria by inhibiting a step in the synthesis of peptidoglycan.
What composes the cell envelope?
The answer is the following:
cell membrane and cell wall