Problem: In the US, one kilowatt-hour (3.6 MJ) of electricity currently causes an average 1.34 pounds (610 g) of CO
2 emission. Assuming the average light bulb is on for 10 hours a day, a 40-watt bulb will cause 196 pounds (89 kg) of CO
2 emission per year. The 6-watt LED equivalent will only cause 30 pounds (14 kg) of CO
2 over the same time span. A building’s carbon footprint from lighting can therefore be reduced by 85% by exchanging all incandescent bulbs for new LEDs if a building previously used only incandescent bulbs.
How much can a building's carbon footprint be reduced by switching to LEDs?
---
Answer: 85%


Problem: Plant circadian rhythms tell the plant what season it is and when to flower for the best chance of attracting pollinators. Behaviors showing rhythms include leaf movement, growth, germination, stomatal/gas exchange, enzyme activity, photosynthetic activity, and fragrance emission, among others. Circadian rhythms occur as a plant entrains to synchronize with the light cycle of its surrounding environment. These rhythms are endogenously generated and self-sustaining and are relatively constant over a range of ambient temperatures. Important features include two interacting transcription-translation feedback loops: proteins containing PAS domains, which facilitate protein-protein interactions; and several photoreceptors that fine-tune the clock to different light conditions. Anticipation of changes in the environment allows appropriate changes in a plant's physiological state, conferring an adaptive advantage. A better understanding of plant circadian rhythms has applications in agriculture, such as helping farmers stagger crop harvests to extend crop availability and securing against massive losses due to weather.
What do plants need to attract to their flowering?
---
Answer: pollinators


Problem: New York City is home to the headquarters of the National Football League, Major League Baseball, the National Basketball Association, the National Hockey League, and Major League Soccer. The New York metropolitan area hosts the most sports teams in these five professional leagues. Participation in professional sports in the city predates all professional leagues, and the city has been continuously hosting professional sports since the birth of the Brooklyn Dodgers in 1882. The city has played host to over forty major professional teams in the five sports and their respective competing leagues, both current and historic. Four of the ten most expensive stadiums ever built worldwide (MetLife Stadium, the new Yankee Stadium, Madison Square Garden, and Citi Field) are located in the New York metropolitan area. Madison Square Garden, its predecessor, as well as the original Yankee Stadium and Ebbets Field, are some of the most famous sporting venues in the world, the latter two having been commemorated on U.S. postage stamps.
Which two sports stadiums of New York City were featured on US stamps?
---
Answer:
the original Yankee Stadium and Ebbets Field