The planet’s wild creatures face a new threat -- from yuppies, empty nesters, singletons and one parent families. Biologists studying the pressure on the planet’s dwindling biodiversity today report on a new reason for alarm. Although the rate of growth in the human population is decreasing, the number of individual households is exploding. Even where populations have actually dwindled -- in some regions of New Zealand, for instance -- the number of individual households has increased, bemuse of divorce, career choice, smaller families and longer lifespans.
Jianguo Liu of Michigan State University and colleagues from Stanford University in California re- port in Nature, in a paper published online in advance, that a greater number of individual house-holds, each containing on average fewer people, meant more pressure on natural resources. Towns and cities began to sprawl as new homes were built. Each household needed fuel to heat and light it; each household r
A. the amount of wildlife is diminishing.
B. the population of human is decreasing.
C. New Zealanders live an unstable life.
D. the structure of families is changing.
The planet’s wild creatures face a new threat -- from yuppies, empty nesters, singletons and one parent families. Biologists studying the pressure on the planet’s dwindling biodiversity today report on a new reason for alarm. Although the rate of growth in the human population is decreasing, the number of individual households is exploding. Even where populations have actually dwindled -- in some regions of New Zealand, for instance -- the number of individual households has increased, bemuse of divorce, career choice, smaller families and longer lifespans.
Jianguo Liu of Michigan State University and colleagues from Stanford University in California re- port in Nature, in a paper published online in advance, that a greater number of individual house-holds, each containing on average fewer people, meant more pressure on natural resources. Towns and cities began to sprawl as new homes were built. Each household needed fuel to heat and light it; each household r
A. the reduction in average home size.
B. the improvement of living conditions.
C. the increasing number of residences.
D. the decline of population growth rate.
Many of the problems we face today are not so new as we think they are. And some of our modern solutions are not so new, either. The problem of energy shortages and the solution of using solar energy go back at least to early Greek cultures. The climate in the coastal areas of Greece 2,500 years ago was characterized by cool winters, much as it is today. At that time, the Greeks heated their homes with small, charcoal-burning heaters. In other words, wood (which is used to make charcoal) was their primary source of energy. However, by the fifth century B C fuel shortages had become common be- cause, in many parts of Greece, the firewood in the forests had been depleted. Once the supply of fire- wood from the local forests ran out, people began to use the wood from olive groves as fuel. But this solution had its own problem. It reduced the olive crop, a valuable resource to the Greeks. By the fourth century B C, the city of Athens banned the use of olive wood for fuel. Wood had to
A. using wood from the olive groves in ancient Greece was a sensible solution to the fuel problem
B. using passive solar energy was more expensive than using wood in ancient Greece
C. the ancient Greeks planted new forests to replace the ones they cut down for firewood
D. the concept of using passive solar energy has been around since at least the fourth century B C
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