268 ❯ STEP 5. Build Your Test-Taking Confidence
31.This biome has cold winters and is known for its
pine forests.
32.This biome is the driest of the land biomes
and experiences the greatest daily temperature
fluctuations.
33.This biome contains trees that drop their leaves
during the winter months.
34.This biome contains plants whose roots cannot
go deep due to the presence of a permafrost.
Questions 35–36: A behavioral endocrinologist cap-
tures male individuals of a territorial bird species over
the course of a year to measure testosterone (T) levels.
In this population, males may play one of two roles:
(1) they may stay in their natal group (the group they
were born in) and help raise their younger siblings, or
(2) they may leave the natal group to establish a new
territory. Use this information and the two histograms
that follow to answer the following questions.
35.Testosterone level in this population may be an
example of
A. adaptive radiation.
B. an adaptation.
C. divergent selection.
D. development.
36.What can you infer about the role of testosterone
in reproduction in this species?
A. It is detrimental to breeding.
B. It aids adult males only.
C. It ensures that all males reproduce equally.
D. It aids in breeding.37.Which of the following is the best explanation
of the results presented in the preceding graph,
collected from the same population in a differ-
ent year?
A. The so-called helper males are actually breeding.
B. The population has stopped growing.
C. Females are equally attracted to adult and
helper males.
D. Testosterone level is affected by many
processes.
Questions 38–41: A researcher grows a population of
ferns in her laboratory. She notices, after a few gener-
ations, a new variant that has a distinct phenotype.
When she tries to breed the original phenotype with
the new one, no offspring are produced. When she
breeds the new variants, however, offspring that look
like the new variant result.
38.What originally caused the change in the variant?
A. Karyotyping
B. Balance polymorphism
C. Mutation
D. PolyploidyBreeding season0102030405060Helper male Breeding maleMean T levelNon-breeding season01020304050Helper male Breeding maleMean T levelBreeding season0102030405060Helper male Breeding maleMean T level