In 1927 at a hotel in Santa Monica, California, crowds gathered to see the stunning feats that hotel porter Pedro Flores, a young immigrant from the Philippines, was performing with a yo-yo. For generations Americans had played with a (1) toy called a bandalore, which, like Flores's yo-yo, consisted of a pair of disks separated by an axle with a string tied around it. The bandalore had been known in Europe for centuries, and Chinese children had played with a similar toy for several thousand years. But Flores's yo-yo had an important difference: it followed the Filipino design in which the string is looped around the axle rather than tiud to it directly. This feature allows users to twirl the yo-yo in wide (2) arcs. This feature also allows users to let it spin in place at the end of its string, among other tricks. Seeing the delighted grins of his onlookers, Flores recognized an immediate business opportunity.

Flores soon left his job at the hotel to devote (3) itself to marketing his toy, which he trademarked with the name "yo-yo" (a name used in the Philippines, reputedly taken from an expression meaning "come back” in the Tagalog language). Trademark in hand, (4) several investors were approached by Flores, but they showed little interest. He was not discouraged, though, and that year he started hand-carving a small number of yo-yos and selling them to neighborhood children. (5) On the other hand, he met a pair of investors from los Angeles-James Lewis and Daniel Stone-who were impressed with his efforts and provided the funding to manufacture the toy on a larger scale.

(6) Children have played with versions of the yo-yo for thousands of years; only the doll is considered to be older. Flores took his toy for a spin throughout the United States, hosting contests in which participants would try to perform yo-yo trick (7) in succession, or in a series. Soon many people could "walk the dog” running a yo-yo along the ground) or (8) collect multiple yo-yos (in different styles and colors). The contests increased excitement about the yo-yo, and sales climbed. By 1929 Flores had opened three factories (9) that employed 600 workers and had produced 300,000 yo-yos everyday to keep up with the demand of his product.

In 1930 Flores sold his company to a businessman Donald F. (10) Duncan he continued to work for the company, traveling around the United States to show what the yo-yo could do. The tournaments he hosted (11) are attracting ever-larger crowds. Though generations of children have grown up knowing only Duncan yo-yos, it was Flores who first popularized the toy under its current name and design. Without him, the yo-yo might never have become the beloved American toy it is today.

While all animals have mechanisms for regulating body temperature, it was commonly (12) understood by most people that only mammals and birds are endotherms-organisms that can raise their body temperature above that of their surroundings by generating heat. Fish are typically ectothermic organisms that depend upon their environment for heat. However, a recent discovery about the opah fish has been making waves among biologists: opah are endotherms.

When biologists measured the body temperature of freshly caught opah, they recorded values that were on average 5°C higher than the water temperature-an entirely unexpected result. While some fish can keep individual body parts, such as the brain, heart, and muscles, warm, the opah was found to maintain a temperature higher than that of the surrounding water throughout its entire body. (13) Even so, the opah kept its body temperature nearly constant (14) one descended to the colder depths. This was a novel (15) observation; whole-body endothermy in a species of fish.

(16) The opah's endothermy stems from two adaptations. First, heat is produced by exercising the unusually large muscles attached to the pectoral (or side) fins: asopah flap these fins for propulsion, the capillary-rich muscles use oxygen in the blood to release energy, including (17) heat—from nutrients. Second, heat loss is minimized by the structure of the opah's gills: they insulated are by a thick layer of fat and contain a net of interleaved blood vessels that are not found in the gills of other fish and that retain heat as the blood absorbs oxygen from seawater. This unique anatomical configuration ensures that body heat is retained.

Whole-body endothermy differentiates opah from other fish and (18) are to have consequences for the habitat and behavior of opah. Albacore tuna, fish that warm only certain body parts, spend most of their time in shallow (19) water. The shallow water is where they rely on solar heat for warmth. In one study, researchers found that albacore spend (20) 58.2 percent of the daytime within 50 meters of the surface of the water. Opah, by contrast, spend less than 10% of the daytime that close to the surface. (21) Albacore spend larger proportions of the daytime at a single depth, while Opah seem to move more frequently, making Opah capable of hunting prey that are found in the deeper parts of the ocean. 

The discovery that opah are endothermic is a small but exciting step in better understanding the many ways in which fish adapt to and (22) ways in which they thrive in the oceans. It is also an example of how a single discovery can overturn a common understanding. As Nicholas Wegner, one of the ecologists who participated in the study, said, "Nature has a way of surprising us with clever strategies where you least expect them."

Tourism has become one of the largest and most profitable industries in the world. Unfortunately, in many places it also contributes to the degradation of landscapes and ecosystems. In response, the industry has developed (23) ecotourism; a type of tourism designed to mitigate environmental damage. When practiced responsibly, ecotourism can be a boon for local (24) economies. Ecotourism also allows beautiful landscapes and rare plants and animals to survive for the years to come.

In many ways, ecotourism companies are similar to other businesses in the tourism (25) industry, they hire, cooks, cleaners, guides, and others to house and feed vacationers and show them around the local area. (26) One benefit is that ecotourism companies try to minimize the impact on the natural environment. To learn how to do this, company leaders often obtain professional credentials such as the Certificate in Sustainable Tourism (27) Management. Offered by the George Washington University and the International Ecotourism Society (TIES). This online learning program gives advice about topics such as measuring environmental effects and following green guidelines. Managers who have received this training (28) and then pass on their knowledge to other workers on the job.

(29) Alaska has long been popular with tourists from the world. Vacationers visit Alaska for (30) it's rugged landscapes and abundant wildlife, but these very features are threatened by pollution. (31) To address this danger, companies such as Alaska Wildland  Adventures provide nature tours and accommodations that minimize  ecosystem disruption. Like other tour companies, Alaska Wildland Adventures. Uses guides to take visitors on whale-watching boat trips and nature hikes to see bear other wildlife. The company's guides, however, take only small groups and (32) are equipped to handle any unforeseen weather emergencies. The company also takes steps to reduce pollution-powering its lodges with hydroelectric systems rather than gas-powered generators-and, like many ecotourism companies, donates a portion of its profits to conservation organizations.

Although ecotourism helps mitigate the damage large groups of visitors cause to fragile ecosystems, it must still be practiced carefully. According to Ayako Ezaki, the director of communications for TIES, companies must take care to limit how many people they bring to a given location: "They need to consider the capacity of the destination," she insists. If the ecotourism industry can successfully balance the potential vulnerability of wilderness areas with the desires of tourists,(33) and if it can harmonize these interests, it holds great promise for nature lovers and the natural world alike.

A popular application on audio devices allows users to increase the playing speed of podcasts or audiobooks, reducing the time required to hear an entire program. This (34) growth has been welcomed by many who want to listen to lengthy programs but lack the time to do so. The convenience of "speed listening" (35) may be its greatest advantage. By obscuring their dramatic effects the practice drains the emotional power from the best audio program stories.

Because speed listening takes advantage of the brain's ability to absorb information quickly and efficiently, it may be an ideal way to consume tutorials or other factual material.  Today's sophisticated devices can minimize many side effects of the speeding-up process: they can prevent voice pitch from rising, for instance, and can cut program lengths with little noticeable change by removing gaps and pauses. On the other hand, these very technologies have a negative impact on stories-the gaps and pauses are often part of the story being told.

A story is rarely meant to move at a uniform, quick speed. Changes in emphasis, hesitations and even throat clearings can convey moods and (36) invoke particular responses in the listener. Episodes of the podcast offered by the storytelling group The Moth, which relate such events as a writer's solo dogsled trek across Arctic America and a doctor's struggle to save the life of Mother Teresa, (37) are delivered by engaging storytellers who connect with their audiences through verbal cues. (38) Speeding up those stories reduces them to streams of information, breaking that connection. Perhaps the most famous audio program of all (39) time Orso Welles's 1938 radio broadcast The War of the Worlds, relied on varied pacing, with interruptions and meaningful silences, to generate a sense of urgency. The dramatic effects that led many of Welles's listeners to believe a Martian invasion was really happening would surely have been lost at high speed.

Forcing a uniformly quick pace onto a story (40) makes reading information on paper more appealing. Consider a long section of dialogue in an (41) audiobook, without pauses, the back-and-forth of the characters runs together, making it difficult for a listener (42) in following the narrative thread. The same is true of stories told by comedians, who are especially dependent on timing (43) without the right pauses and breaks, many of the best laugh lines may not even make sense. 

It takes time to absorb the nuances of stories; they engage not just our verbal understanding but also our memories, impressions, and feelings. (44) Listening at high speed, we may miss the point of tuning in at all.