The problem: Answer a question about this article:
For example, consider electronpositron annihilation, in which the rest mass of individual particles is destroyed, but the inertia equivalent of the system of the two particles (its invariant mass) remains (since all energy is associated with mass), and this inertia and invariant mass is carried off by photons which individually are massless, but as a system retain their mass. This is a reversible process the inverse process is called pair creation in which the rest mass of particles is created from energy of two (or more) annihilating photons. In this system the matter (electrons and positrons) is destroyed and changed to non-matter energy (the photons). However, the total system mass and energy do not change during this interaction.
What is the inverse process called?
****
The answer: pair creation

The problem: Answer a question about this article:
In Darwin's time there was no agreed-upon model of heredity; in Chapter I Darwin admitted, "The laws governing inheritance are quite unknown." He accepted a version of the inheritance of acquired characteristics (which after Darwin's death came to be called Lamarckism), and Chapter V discusses what he called the effects of use and disuse; he wrote that he thought "there can be little doubt that use in our domestic animals strengthens and enlarges certain parts, and disuse diminishes them; and that such modifications are inherited", and that this also applied in nature. Darwin stated that some changes that were commonly attributed to use and disuse, such as the loss of functional wings in some island dwelling insects, might be produced by natural selection. In later editions of Origin, Darwin expanded the role attributed to the inheritance of acquired characteristics. Darwin also admitted ignorance of the source of inheritable variations, but speculated they might be produced by environmental factors. However, one thing was clear: whatever the exact nature and causes of new variations, Darwin knew from observation and experiment that breeders were able to select such variations and produce huge differences in many generations of selection. The observation that selection works in domestic animals is not destroyed by lack of understanding of the underlying hereditary mechanism.
What did Darwin learn about about the characteristics of domestic animals?
****
The answer: use in our domestic animals strengthens and enlarges certain parts, and disuse diminishes them

The problem: Answer a question about this article:
The main passenger airport serving the metropolis and the state is Melbourne Airport (also called Tullamarine Airport), which is the second busiest in Australia, and the Port of Melbourne is Australia's busiest seaport for containerised and general cargo. Melbourne has an extensive transport network. The main metropolitan train terminus is Flinders Street Station, and the main regional train and coach terminus is Southern Cross Station. Melbourne is also home to Australia's most extensive freeway network and has the world's largest urban tram network.
What is Melbourne's main regional train and coach terminus called?
****
The answer: Southern Cross Station

The problem: Answer a question about this article:
By 1200, the Swiss plateau comprised the dominions of the houses of Savoy, Zahringer, Habsburg, and Kyburg. Some regions (Uri, Schwyz, Unterwalden, later known as Waldstatten) were accorded the Imperial immediacy to grant the empire direct control over the mountain passes. With the extinction of its male line in 1263 the Kyburg dynasty fell in AD 1264; then the Habsburgs under King Rudolph I (Holy Roman Emperor in 1273) laid claim to the Kyburg lands and annexed them extending their territory to the eastern Swiss plateau.
Which Holy Roman Emperor were the Habsburgs under in 1273 AD?
****
The answer:
King Rudolph I