On July 23, 1854, a clipper ship called the Flying Cloud entered San Francisco ______blank left New York Harbor under the guidance of Captain Josiah Perkins Creesy and his wife, navigator Eleanor Creesy, a mere 89 days and 8 hours earlier, the celebrated ship set a record that would stand for 135 years.

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.

Archaeologists have estimated that the pre-Columbian Native American city of Cahokia, located across the Mississippi River from modern-day St. Louis, Missouri, had as many as 20,000 inhabitants in the year 1150 ______blank it one of the largest cities in North America at the time.

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.

Working from an earlier discovery of Charpentier’s, chemists Emmanuelle Charpentier and Jennifer Doudna—winners of the 2020 Nobel Prize in Chemistry—re-created and then reprogrammed the so-called “genetic scissors” of a species of DNA-cleaving bacteria ______blank a tool that is revolutionizing the field of gene technology.

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

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.

During the American Civil War, Thomas Morris Chester braved the front lines as a war correspondent for the Philadelphia Press. Amplifying the voices and experiences of Black soldiers ______blank of particular importance to Chester, who later became an activist and lawyer during the postwar Reconstruction period.

Gathering accurate data on water flow in the United States is challenging because of the country’s millions of miles of ______blank the volume and speed of water at any given location can vary drastically over time.

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 her book The Woman Warrior: Memoirs of a Girlhood Among Ghosts, author Maxine Hong Kingston examines themes ______blank childhood, womanhood, and Chinese American identity by intertwining autobiography and mythology.

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.

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.

To survive when water is scarce, embryos inside African turquoise killifish eggs ______blank a dormant state known as diapause. In this state, embryonic development is paused for as long as two years—longer than the life span of an adult killifish.

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.