Problem: Incandescent light bulbs consist of an air-tight glass enclosure (the envelope, or bulb) with a filament of tungsten wire inside the bulb, through which an electric current is passed. Contact wires and a base with two (or more) conductors provide electrical connections to the filament. Incandescent light bulbs usually contain a stem or glass mount anchored to the bulb's base that allows the electrical contacts to run through the envelope without air or gas leaks. Small wires embedded in the stem in turn support the filament and its lead wires.
What is the name of the air-tight glass enclosure in an incandescent bulb?
The answer is the following: the envelope

Problem: As female fetuses have two X chromosomes and male ones a XY pair, the chromosome Y is the responsible for producing male differentiation on the defect female development. The differentiation process is driven by androgen hormones, mainly testosterone and dihydrotestosterone (DHT). The newly formed testicles in the fetus are responsible for the secretion of androgens, that will cooperate in driving the sexual differentiation of the developing fetus, included its brain. This results in sexual differences between males and females. This fact has led some scientists to test in various ways the result of modifying androgen exposure levels in mammals during fetus and early life.
What have scientist began to test due to the fact that adrogen results in sexual differences?
The answer is the following: the result of modifying androgen exposure levels in mammals during fetus and early life

Problem: During the latter half of the 20th century, Washington University transitioned from a strong regional university to a national research institution. In 1957, planning began for the construction of the "South 40," a complex of modern residential halls. With the additional on-campus housing, Washington University, which had been predominantly a "streetcar college" of commuter students, began to attract a more national pool of applicants. By 1964, over two-thirds of incoming students came from outside the St. Louis area.
What proportion of students at Washington University came from outside the St. Louis area by 1964?
The answer is the following: over two-thirds

Problem: One of the first recorded instances of translation in the West was the rendering of the Old Testament into Greek in the 3rd century BCE. The translation is known as the "Septuagint", a name that refers to the seventy translators (seventy-two, in some versions) who were commissioned to translate the Bible at Alexandria, Egypt. Each translator worked in solitary confinement in his own cell, and according to legend all seventy versions proved identical. The Septuagint became the source text for later translations into many languages, including Latin, Coptic, Armenian and Georgian.
Why is the translation of the Old Testament into Greek known as the Septuagint?
The answer is the following:
seventy translators