Mastering Biology Practice Q's Ch 22-
26 Exam Question & Answers 2025
Which of the following is an observation or inference on
which natural selection is based?
(A) Individuals do not vary in their heritable
characteristics.
(B) Only well-adapted individuals produce offspring.
(C) Species produce more offspring than the environment
can support.
(D) Nearly all of each individual's offspring will survive
and reproduce. - CORRECT ANSWERS ✅C) Species
produce more offspring than the environment can support
Which of the following observations helped Darwin shape
his concept of descent with modification?
(A) Species diversity declines farther from the equator.
(B) Fewer species live on islands than on the nearest
continents.
(C) Birds live on islands located farther from the mainland
than the birds' maximum nonstop flight distance.
(D) South American temperate plants are more similar to
South American tropical plants than to European
temperate ones. - CORRECT ANSWERS ✅D) South
American temperate plants are more similar to South
American tropical plants than to European temperate
ones.
,Mastering Biology Practice Q's Ch 22-
26 Exam Question & Answers 2025
Within six months of effectively using methicillin to treat
S. aureus infections in a community, all new S. aureus
infections were caused by a resistant strain (MRSA). How
can this best be explained?
(A) A patient must have become infected with MRSA from
another community.
(B) In response to the drug, S. aureus began making
drug-resistant versions of the protein targeted by the
drug.
(C) Some drug-resistant bacteria were present at the start
of treatment, and natural selection increased their
frequency.
(D) S. aureus evolved to resist vaccines. - CORRECT
ANSWERS ✅C) Some drug-resistant bacteria were
present at the start of treatment, and natural selection
increased their frequency.
DNA sequences in many human genes are very similar to
the sequences of corresponding genes in chimpanzees.
The most likely explanation for this result is that
(A) humans and chimpanzees share a relatively recent
common ancestor.
(B) humans evolved from chimpanzees.
(C) chimpanzees evolved from humans.
,Mastering Biology Practice Q's Ch 22-
26 Exam Question & Answers 2025
(D) convergent evolution led to the DNA similarities. -
CORRECT ANSWERS ✅A) humans and chimpanzees
share a relatively recent common ancestor.
The upper forelimbs of humans and bats have fairly
similar skeletal structures, whereas the corresponding
bones in whales have very different shapes and
proportions. However, genetic data suggest that all three
kinds of organisms diverged from a common ancestor at
about the same time. Which of the following is the most
likely explanation for these data?
(A) Forelimb evolution was adaptive in people and bats,
but not in whales.
(B) Natural selection in an aquatic environment resulted
in significant changes to whale forelimb anatomy.
(C) Genes mutate faster in bats than in humans or
whales.
(D) Whales are not properly classified as mammals. -
CORRECT ANSWERS ✅B) Natural selection in an
aquatic environment resulted in significant changes to
whale forelimb anatomy.
Natural selection changes allele frequencies because
some survive and reproduce better than others.
(A) alleles
, Mastering Biology Practice Q's Ch 22-
26 Exam Question & Answers 2025
(B) loci
(C) species
(D) individuals - CORRECT ANSWERS ✅D) individuals
No two people are genetically identical, except for
identical twins. The main source of genetic variation
among humans is
(A) new mutations that occurred in the preceding
generation.
(B) genetic drift.
(C) the reshuffling of alleles in sexual reproduction.
(D) environmental effects. - CORRECT ANSWERS ✅C)
the reshuffling of alleles in sexual reproduction.
If the nucleotide variability of a locus equals 0%, what is
the gene variability and number of alleles at that locus?
(A) gene variability = 0% gene variability = 0%; number
of alleles = 0 number of alleles = 0
(B) gene variability = 0% gene variability = 0%; number
of alleles = 1 number of alleles = 1
(C) gene variability = 0% gene variability = 0%; number
of alleles = 2 number of alleles = 2
26 Exam Question & Answers 2025
Which of the following is an observation or inference on
which natural selection is based?
(A) Individuals do not vary in their heritable
characteristics.
(B) Only well-adapted individuals produce offspring.
(C) Species produce more offspring than the environment
can support.
(D) Nearly all of each individual's offspring will survive
and reproduce. - CORRECT ANSWERS ✅C) Species
produce more offspring than the environment can support
Which of the following observations helped Darwin shape
his concept of descent with modification?
(A) Species diversity declines farther from the equator.
(B) Fewer species live on islands than on the nearest
continents.
(C) Birds live on islands located farther from the mainland
than the birds' maximum nonstop flight distance.
(D) South American temperate plants are more similar to
South American tropical plants than to European
temperate ones. - CORRECT ANSWERS ✅D) South
American temperate plants are more similar to South
American tropical plants than to European temperate
ones.
,Mastering Biology Practice Q's Ch 22-
26 Exam Question & Answers 2025
Within six months of effectively using methicillin to treat
S. aureus infections in a community, all new S. aureus
infections were caused by a resistant strain (MRSA). How
can this best be explained?
(A) A patient must have become infected with MRSA from
another community.
(B) In response to the drug, S. aureus began making
drug-resistant versions of the protein targeted by the
drug.
(C) Some drug-resistant bacteria were present at the start
of treatment, and natural selection increased their
frequency.
(D) S. aureus evolved to resist vaccines. - CORRECT
ANSWERS ✅C) Some drug-resistant bacteria were
present at the start of treatment, and natural selection
increased their frequency.
DNA sequences in many human genes are very similar to
the sequences of corresponding genes in chimpanzees.
The most likely explanation for this result is that
(A) humans and chimpanzees share a relatively recent
common ancestor.
(B) humans evolved from chimpanzees.
(C) chimpanzees evolved from humans.
,Mastering Biology Practice Q's Ch 22-
26 Exam Question & Answers 2025
(D) convergent evolution led to the DNA similarities. -
CORRECT ANSWERS ✅A) humans and chimpanzees
share a relatively recent common ancestor.
The upper forelimbs of humans and bats have fairly
similar skeletal structures, whereas the corresponding
bones in whales have very different shapes and
proportions. However, genetic data suggest that all three
kinds of organisms diverged from a common ancestor at
about the same time. Which of the following is the most
likely explanation for these data?
(A) Forelimb evolution was adaptive in people and bats,
but not in whales.
(B) Natural selection in an aquatic environment resulted
in significant changes to whale forelimb anatomy.
(C) Genes mutate faster in bats than in humans or
whales.
(D) Whales are not properly classified as mammals. -
CORRECT ANSWERS ✅B) Natural selection in an
aquatic environment resulted in significant changes to
whale forelimb anatomy.
Natural selection changes allele frequencies because
some survive and reproduce better than others.
(A) alleles
, Mastering Biology Practice Q's Ch 22-
26 Exam Question & Answers 2025
(B) loci
(C) species
(D) individuals - CORRECT ANSWERS ✅D) individuals
No two people are genetically identical, except for
identical twins. The main source of genetic variation
among humans is
(A) new mutations that occurred in the preceding
generation.
(B) genetic drift.
(C) the reshuffling of alleles in sexual reproduction.
(D) environmental effects. - CORRECT ANSWERS ✅C)
the reshuffling of alleles in sexual reproduction.
If the nucleotide variability of a locus equals 0%, what is
the gene variability and number of alleles at that locus?
(A) gene variability = 0% gene variability = 0%; number
of alleles = 0 number of alleles = 0
(B) gene variability = 0% gene variability = 0%; number
of alleles = 1 number of alleles = 1
(C) gene variability = 0% gene variability = 0%; number
of alleles = 2 number of alleles = 2
