Protons are positively charged subatomic particles. ____, electrons are negatively charged.

Commercial whale hunting was banned by the International Whaling Commission in 1986. ____, some indigenous communities are allowed to hunt whales.

The 17th-century Japaanese poet Basho created a new poetic form called haibun. ____, the form memorializes a long journey by combining haiku and prose.

In 1933 the New York Metropolitan Museum displayed three statues of Etruscan warriors that turned out to be forgeries. ____, the curators were fooled.

A wave of hysteria over suspected witches swept Salem, Massachusetts, in 1692. ____, supposed witches were persecuted in Scotland in the 16th century.

Greenland occupies some 836,000 square miles of land. ____, Saudi Arabia spans about 830,000 square miles.

Many cultures developed warrior codes. ____, Japanese samurai adopted the bushido code to guide them in battle.

Wheat went from a wild grass in the Middle East 12,000 years ago to one of the most cultivated crops on Earth. ____, it's an evolutionary success story.

The impeachment of U.S. presidents, which can lead to their removal, is extremely rare. ____ it's happened only a handful of times in American history.

The killdeer's name suggests that it's a type of deer. ____, it's a bird that's named for the sound of its call.

Psychoanalysis became widely popular in Argentina in the 1950s and 60s. ____, the country experienced a therapy boom.

Author Victor Hugo wrote Les Miserables while exiled from France. ____, Niccolo Machiavelli wrote The Prince under self-imposed exile from Florence.

Musicals generally use spoken dialogue as well as songs to convey the story. ____, operas are usually fully sung.

In the Maillard reaction, compounds in food reassemble into more flavorful ones as heat is applied. ____, it's what makes food taste better when cooked.

Although ostriches are birds, they're too heavy to fly. ____, they can sprint up to 43 miles per hour.

Electric cars were invented in the 19th century. ____, lower-cost gas-powered cars proved more popular.

Bottlenose dolphins can recognize themselves in mirrors. ____, elephants examine their reflections for stray marks.

The English horn produces sound when wind, or breath, passes through it. ____, it is a wind instrument.

Glassmaker Leopold Blaschka went on an ocean voyage in the 1850s. ____, he was inspired to make intricate glass models of the sea creatures he witnessed.

When churches were threatened with demolition in 1980s Bucharest, engineers moved them away on giant rail tracks. ____, they made entire buildings portable.

Seawater contains particles of gold. ____, they're so small that they wouldn't be cost-effective to collect.