feudal aristocracy c. road construction

9. Paola is an engineer at an environmental con-

sulting firm. Her job is to analyze air quality and the amount of toxic emissions due to highway
traffic. The amount of emissions depends on the number of lanes and on the average speed of the
traffic. The greater the number of lanes and the slower the cars move, the higher the amount of
toxic emissions. Which of these choices corre- sponds to the highest amount of toxic emissions
into the atmosphere? a. a two-lane highway at 2
A
.
M
. on Monday

b. a four-lane highway at 2

A
.
M
. on Tuesday

c. a two-lane highway at 5:30

P
.
M
. on Wednesday

d. a four-lane highway at 5:30

P
.
M
. on Thursday

e. a two-lane highway at 5:30

P
.
M
. on Sunday

10. Many types of learning occur only at particular

times called sensitive periods. For example, chil- dren born blinded by cataracts can learn to see if
the cataracts are removed by age 10. If the cataracts are removed later in life, these people
can see random shapes and colors, but are unable to interpret them. A scientist is inter-
ested in knowing whether there is a sensitive period for chaffinch birds to learn to sing the
species song, and if so, how long this period lasts. Which of the following experiments would be
most suitable for his purpose? a. Take 20 just-hatched chaffinch birds from
their environment. Bring them up in isola- tion, so that they are not exposed to their
species song. Every week, return one bird to its environment and keep a record of the
number of weeks it spent in isolation and whether it learned to sing.

b. Take 20 just-hatched chaffinch birds from

their environment. Bring them up with birds of a different species, so they are exposed to
songs that do not resemble their own. Every week, return one bird to its environment and
keep a record of the number of weeks it spent with birds of a different species and which
song it learned to sing.

c. Take 20 just-hatched chaffinch birds from

their environment. Every day, play them a recording of the song of their species. Reward
with food the birds that try to imitate the recorded sound, and note the number of
weeks it took each one to learn to sing.

d. Take 20 chaffinch birds, of any age. Every day,

play a recording of the song of another bird species. Record the age of every bird that was
able to learn the song of the other bird species.

e. Bring up 20 just-hatched chaffinch birds

among both adult chaffinch birds and adult birds of another species. Record the amount
of time it took just-hatched birds to sing, and determine whether the presence of the other
species improved or deterred their ability to learn to sing their species song.
Pretest Answers and Explanations

1. b. Longitude is the only factor on the list that does

NOT influence climate. In places on Earth that have the same longitude, noon occurs at the
same time, but those places don’t necessarily have the same climate. For example, Maine and
Florida are at approximately the same longitude, but the climate in Maine is much colder than
Florida, because Florida is closer to the equator latitude, choice a. Altitude can influence cli-
mate, choice c. There is often snow at a top of a mountain when there isn’t any at its base. Ocean
currents can also influence climate, choice d. The Gulf stream is a warm Atlantic Ocean cur-
rent that provides countries in Northern Europe with a warmer climate than places at the same
latitude in Canada. The presence of mountain ranges can influence climate, choice e. For
example, it doesn’t rain much in Nevada’s Great Basin due to the Sierra Nevada Mountains.

2. d. Metabolic rate per gram of body weight is

higher in small animals. You can infer that a large animal has the lowest metabolic rate per
gram of its body weight. The largest animal on the list is the elephant.

3. c. Choice a is incorrect because the population of

wolves decreased during some periods, resulting in a net decrease from 1955 to 1980. Choice b is
incorrect because although the population of deer decreased during every period, the decrease
was sometimes more dramatic than during other times, i.e., the rate of decrease was not
constant. Choice d is incorrect because the pop- ulation of deer did not increase over time.
Choice e is incorrect because the population of deer in 1975 was 120, not 45.
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