Emperor Ashoka ruled the Maurya Empire in South Asia from roughly 270 to 232 BCE. He is known for enforcing a moral code called the Law of Piety, which established the sanctity of animal ______blank the just treatment of the elderly, and the abolition of the slave trade.

Despite being cheap, versatile, and easy to produce, ______blank they are made from nonrenewable petroleum, and most do not biodegrade in landfills.

In 1903, environmentalist John Muir guided President Theodore Roosevelt on a scenic, sprawling trip through California’s Yosemite Valley. Upon returning from the three-day excursion, Roosevelt ______blank to conserve the nation’s wilderness areas, a vow he upheld for his remaining six years in office.

Bonnie Buratti of NASA’s Jet Propulsion Laboratory ______blank data about Saturn’s rings collected by the Cassini spacecraft when she made an interesting discovery: the tiny moons embedded between and within Saturn’s rings are shaped by the buildup of ring material on the moons’ surfaces.

After a spate of illnesses as a child, Wilma Rudolph was told she might never walk again. Defying all odds, Rudolph didn’t just walk, she ______blank the 1960 Summer Olympics in Rome, she won both the 100- and 200-meter dashes and clinched first place for her team in the 4x100-meter relay, becoming the first US woman to win three gold medals in a single Olympics.

In 1637, the price of tulips skyrocketed in Amsterdam, with single bulbs of rare varieties selling for up to the equivalent of $200,000 in today’s US dollars. Some historians ______blank that this “tulip mania” was the first historical instance of an asset bubble, which occurs when investors drive prices to highs not supported by actual demand.

In the 1970s, Janaki Ammal, a prominent botanist, emerged as a powerful voice in India’s environmental conservation movement. Her exhaustive chromosomal survey of plants in Silent Valley, a pristine tropical forest in Kerala, India, that is home to nearly 1,000 species of native flora (many of which are endangered), ______blank instrumental in the government’s decision to preserve the forest.

The radiation that ______blank during the decay of radioactive atomic nuclei is known as gamma radiation.

Rabinal Achí is a precolonial Maya dance drama performed annually in Rabinal, a town in the Guatemalan highlands. Based on events that occurred when Rabinal was a city-state ruled by a king, ______blank had once been an ally of the king but was later captured while leading an invading force against him.

The artistic talents of Barbara Chase-Riboud, most known for her 1979 historical novel Sally Hemings and the conversation it inspired, ______blank limited to the realm of prose: she first excelled in sculpture, where her affinity for bronze—a material she described as “timeless” due to its use across eras and cultures—became part of her artistic identity.

Generations of mystery and horror ______blank have been influenced by the dark, gothic stories of celebrated American author Edgar Allan Poe (1809–1849).

On April 5, 1977, Kitty Cone and 150 other disability rights activists entered a San Francisco federal building. After pleading for years—to no effect—for the passage of key antidiscrimination legislation, ______blank until their demands were addressed. Finally, on April 28, the legislation was signed.

A subseasonal weather forecast attempts to predict weather conditions three to four weeks in ______blank its predictions are therefore more short-term than those of the seasonal forecast, which attempts to predict the weather more than a month in advance.

African American Percy Julian was a scientist and entrepreneur whose work helped people around the world to see. Named in 1999 as one of the greatest achievements by a US chemist in the past hundred years, ______blank led to the first mass-produced treatment for glaucoma.

In 1966, Emmett Ashford became the first African American to umpire a Major League Baseball game. His energetic gestures announcing when a player had struck out and his habit of barreling after a hit ball to see if it would land out of ______blank transform the traditionally solemn umpire role into a dynamic one.