Human-made (synthetic) fibers used in clothes and many other consumer products are more durable than most natural plant ______blank the manufacture of synthetic fibers requires toxic chemical solvents that can pollute air and water.

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.

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.

Professional American football player Fred Cox invented one of the world’s most popular toys. In the 1970s, he came up with the idea for the Nerf football, which ______blank of the harder and heavier regulation football.

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

Atoms in a synchrotron, a type of circular particle accelerator, travel faster and faster until they ______blank a desired energy level, at which point they are diverted to collide with a target, smashing the atoms.

Sociologist Alton Okinaka sits on the review board tasked with adding new sites to the Hawai‘i Register of Historic Places, which includes Pi‘ilanihale Heiau and the ‘Ōpaeka‘a Road Bridge. Okinaka doesn’t make such decisions ______blank all historical designations must be approved by a group of nine other experts from the fields of architecture, archaeology, history, and Hawaiian culture.

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

Classical composer Florence Price’s 1927 move to Chicago marked a turning point in her career. It was there that Price premiered her First Symphony—a piece that was praised for blending traditional Romantic motifs with aspects of Black folk music—and ______blank supportive relationships with other Black artists.

In addition to advocating for South America’s independence in two political treatises, the Cartagena Manifesto and the Letter from Jamaica, Simón Bolívar personally led armies against the Spanish, liberating three South American territories—New Granada (present-day Colombia and Panama), Venezuela, and Quito (present-day ______blank from colonial rule.

In assessing the films of Japanese director Akira Kurosawa, ______blank have missed his equally deep engagement with Japanese artistic traditions such as Noh theater.

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.

Ten of William Shakespeare’s plays are classified as histories. Although each one of these plays, which include Henry V and Richard III, ______blank on a single historical figure (specifically, an English king), some, such as Henry VI Part One and Henry VI Part Two, feature different episodes from the same monarch’s life.     

In 2008, two years after the death of science fiction writer Octavia Butler, the Huntington Library in ______blank received a collection of more than 8,000 items, including Butler’s private notes, research materials, manuscripts, photos, and drawings. Today, the Octavia E. Butler Collection is one of the most researched archives at the library.

When they were first discovered in Australia in 1798, duck-billed, beaver-tailed platypuses so defied categorization that one scientist assigned them the name Ornithorhynchus paradoxus: “paradoxical bird-snout.” The animal, which lays eggs but also nurses ______blank young with milk, has since been classified as belonging to the monotremes group.