The longevity of nuclear power plants has averaged about
A) 20 to 25 years due to unexpectedly high levels of corrosion and embrittlement.
B) 40 to 50 years, longer than imagined, because neutrons tend to stabilize the building materials.
C) 10 years, only about 25 of their expected life, due to the need for new government-mandated safety designs.
D) 40 years, as expected, due to routine maintenance and the replacement with new longer-lasting materials.
Question 2
Some beetles escape from a ship and fly to a small island covered with grass but with no trees or beetle predators. As the beetles feed, they destroy all the grasses. But with abundant food, the beetle population soars, doubling in size every month.
After about a year, the population crashes as thousands of beetles have destroyed almost all of the plants and there is little left to feed the large population. This scenario best illustrates A) constant growth followed by equilibrium.
B) a population that has stabilized near its carrying capacity.
C) exponential growth followed by a population crash.
D) the fact that the beetles have strong competition from other species for food supply.
Three routes of tissue-level transport in plants: transmembrane, symplastic, and apoplastic.
Plants
(a) The site of Zhoukoudian outside of Beijing, China, spans several hundred thousand years and (b)
Acid Rain and Power Plant Emissions
Carbon Dioxide Concentrations for 400,000 years
Estimates of carbon stored in the plants and soils of different ecosystems.