1 Exampromax - Stuvia US 2025/2026
Bio 172 UH Manoa Questions and Answers
(100% Correct Answers) Already Graded A+
Endoderm
Mesoderm
Ectoderm
Ans: Three embryonic layers. Endoderm being the inner most layer and
Ectoderm being the outermost.
What traits are present in the early stages of development that would not
allow you to determine if the animal is a protostome or deuterostome?
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Exampromax - Stuvia US
A) Radial Cleavage
B) presence of endoderm, mesoderm, and ectoderm
c) Coelom formed by splitting the mesodermal mass
D) Anus forms from blastopore
E) The developmental fate of each embryonic cell is fully determined
Ans: B) presence of endoderm, mesoderm, and ectoderm
Coelom
Ans: Internal body cavity derived from the mesoderm
Blastopore
Ans: The opening that develops into the mouth in protostomes and the anus in
deuterostomes
Radial Symmetry
Ans: Can be split on multiple planes and be symmetrical (Circle)
Ex. Adult Cnidaria
Bilateral symmetry
, 2 Exampromax - Stuvia US 2025/2026
Ans: Will only be symmetrical if split on one line, all others will not be
symmetrical (humans)
Ex. Nematoda
Rotational symmetry
Ans: Division of the body into two halves divides it into two copies of the same
half with one rotated 180 degrees.
Ex. Ctenophora
Asymmetry
Ans: No symmetry in any split
Ex. Porifera
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Which is not a monophyletic group?
Exampromax - Stuvia US
A) Opisthokonta
B) Bilateria
C) Cnidaria
D) Ctenophora
E) Porifera
Ans: A) Opisthokonta
Which is true about animal evolutionary history?
A) the Cambrian explosion led to the appearance of the Ediacaran biota
B) the Cambrian explosion occurred around 100 MYA
C) several extant phyla first appear in the fossil record from the Cambrian
period
D) many fossils dating from the Cambrian explosion represent species that
survive today
E) the Cambrian explosion was caused by a rapid increase in Earth's
atmospheric nitrogen
, 3 Exampromax - Stuvia US 2025/2026
Ans: C) Several extant phyla first appear in the fossil record from the Cambrian
Period
Ediacaran Period
Ans: before Cambrian period, about 635-543 MYA
Cambrian Explosion/Period
Ans: the most rapid evolution of new animal phyla and animal diversity in
Earth's history about 542-488 MYA
Which of the following is not typical of most animals?
© 2025 Assignment Expert
A) Specialized tissues
Exampromax - Stuvia US
B) a stage of development called gastrulation
C) possession of hox genes
D) alternation of generations between diploid and haploid lifestages
E) food obtained via heterotrophy
Ans: D) Alternation of generations between diploid and haploid lifestages
Hox Genes
Ans: Responsible for the general body pattern of most animals
Gastrulation
Ans: results in the formation of the primitive gut (archenteron) or digestive cavity
and the formation of the embryonic layers.
Organogenesis
Ans: formation of organs
Which of the following is true of the animal phylogenetic tree?
A) fossils provide the best source of information for determining the animal
phylogenetic tree
, 4 Exampromax - Stuvia US 2025/2026
B) major accepted clades of the animal phylogeny have remained constant
over the past 50 years
C) Future DNA evidence is likely to demonstrate that the Bilateria is the
most primitive animal clade
D) Eumetazoans include more species than Metazoans
E) As more DNA is sequenced and analyzed from more animals, future
changes to major surviving clades of the animal phylogenetic tree become
less likely.
Ans: E) As more DNA is sequenced and analyzed from more animals, future
changes to major surviving clades of the animal phylogenetic tree become less
likely
© 2025 Assignment Expert
Which of the following is not true of the coelom?
Exampromax - Stuvia US
A) it may be present in triploblastic organisms
B) it is a cavity the houses internal organs
C) it is derived from mesoderm
D) it is present in all animals
E) it usually contain fluids
Ans: D) it is present in all animals
Triploblastic
Ans: Having 3 embryonic layers (endoderm, mesoderm, and ectoderm)
Diploblastic
Ans: Having 2 embryonic layers (endoderm and ectoderm).
Which of the following does not play a major role in Earth's post-Cambrian
animal evolution?
A) evolution among plants
B) meteor strikes
C) Change in distance between the Earth and the sun
Bio 172 UH Manoa Questions and Answers
(100% Correct Answers) Already Graded A+
Endoderm
Mesoderm
Ectoderm
Ans: Three embryonic layers. Endoderm being the inner most layer and
Ectoderm being the outermost.
What traits are present in the early stages of development that would not
allow you to determine if the animal is a protostome or deuterostome?
© 2025 Assignment Expert
Exampromax - Stuvia US
A) Radial Cleavage
B) presence of endoderm, mesoderm, and ectoderm
c) Coelom formed by splitting the mesodermal mass
D) Anus forms from blastopore
E) The developmental fate of each embryonic cell is fully determined
Ans: B) presence of endoderm, mesoderm, and ectoderm
Coelom
Ans: Internal body cavity derived from the mesoderm
Blastopore
Ans: The opening that develops into the mouth in protostomes and the anus in
deuterostomes
Radial Symmetry
Ans: Can be split on multiple planes and be symmetrical (Circle)
Ex. Adult Cnidaria
Bilateral symmetry
, 2 Exampromax - Stuvia US 2025/2026
Ans: Will only be symmetrical if split on one line, all others will not be
symmetrical (humans)
Ex. Nematoda
Rotational symmetry
Ans: Division of the body into two halves divides it into two copies of the same
half with one rotated 180 degrees.
Ex. Ctenophora
Asymmetry
Ans: No symmetry in any split
Ex. Porifera
© 2025 Assignment Expert
Which is not a monophyletic group?
Exampromax - Stuvia US
A) Opisthokonta
B) Bilateria
C) Cnidaria
D) Ctenophora
E) Porifera
Ans: A) Opisthokonta
Which is true about animal evolutionary history?
A) the Cambrian explosion led to the appearance of the Ediacaran biota
B) the Cambrian explosion occurred around 100 MYA
C) several extant phyla first appear in the fossil record from the Cambrian
period
D) many fossils dating from the Cambrian explosion represent species that
survive today
E) the Cambrian explosion was caused by a rapid increase in Earth's
atmospheric nitrogen
, 3 Exampromax - Stuvia US 2025/2026
Ans: C) Several extant phyla first appear in the fossil record from the Cambrian
Period
Ediacaran Period
Ans: before Cambrian period, about 635-543 MYA
Cambrian Explosion/Period
Ans: the most rapid evolution of new animal phyla and animal diversity in
Earth's history about 542-488 MYA
Which of the following is not typical of most animals?
© 2025 Assignment Expert
A) Specialized tissues
Exampromax - Stuvia US
B) a stage of development called gastrulation
C) possession of hox genes
D) alternation of generations between diploid and haploid lifestages
E) food obtained via heterotrophy
Ans: D) Alternation of generations between diploid and haploid lifestages
Hox Genes
Ans: Responsible for the general body pattern of most animals
Gastrulation
Ans: results in the formation of the primitive gut (archenteron) or digestive cavity
and the formation of the embryonic layers.
Organogenesis
Ans: formation of organs
Which of the following is true of the animal phylogenetic tree?
A) fossils provide the best source of information for determining the animal
phylogenetic tree
, 4 Exampromax - Stuvia US 2025/2026
B) major accepted clades of the animal phylogeny have remained constant
over the past 50 years
C) Future DNA evidence is likely to demonstrate that the Bilateria is the
most primitive animal clade
D) Eumetazoans include more species than Metazoans
E) As more DNA is sequenced and analyzed from more animals, future
changes to major surviving clades of the animal phylogenetic tree become
less likely.
Ans: E) As more DNA is sequenced and analyzed from more animals, future
changes to major surviving clades of the animal phylogenetic tree become less
likely
© 2025 Assignment Expert
Which of the following is not true of the coelom?
Exampromax - Stuvia US
A) it may be present in triploblastic organisms
B) it is a cavity the houses internal organs
C) it is derived from mesoderm
D) it is present in all animals
E) it usually contain fluids
Ans: D) it is present in all animals
Triploblastic
Ans: Having 3 embryonic layers (endoderm, mesoderm, and ectoderm)
Diploblastic
Ans: Having 2 embryonic layers (endoderm and ectoderm).
Which of the following does not play a major role in Earth's post-Cambrian
animal evolution?
A) evolution among plants
B) meteor strikes
C) Change in distance between the Earth and the sun
