Questions All Solved Correct 2025
Graded to Pass.
1. The last common ancestor of all animals was probably a ________.
A) unicellular chytrid
B) unicellular yeast
C) multicellular algae
D) multicellular fungus
E) flagellated protist - Answer E) flagellated protist
1. What synapomorphy distinguishes animals as a monophyletic group, distinct from
choanoflagellates?
A) Sexual reproduction
B) Heterotrophy
C) Multicellularity
D) No cell walls - Answer C) Multicellularity
1. The evolution of animal species has been prolific. Much of this diversity is a result of the
evolution of novel ways to _____.
A) arrange cells into tissues
B) form an embryo and establish a basic body plan
C) sense, feed, and move
D) become terrestrial - Answer C) sense, feed, and move
1. The most ancient branching point in animal phylogeny is the characteristic of having _____.
A) radial or bilateral symmetry
B) diploblastic or triploblastic embryos
C) true tissues or no tissues
D) a body cavity or no body cavity - Answer A) radial or bilateral symmetry
,D. contributed to a hydrostatic skeleton, allowing greater range of motion - Answer D.
contributed to a hydrostatic skeleton, allowing greater range of motion
1. An adult animal that possesses bilateral symmetry would most likely also be _____.
A) a deuterostome
B) coelomate
C) diploblastic
triploblastic - Answer triploblastic
1. Animals with a cephalized body structure would be better able to ________.
A) detect and obtain food
B) extend a nerve net in all directions from a central point
C) rely on filter feeding
D) remain as an acoelomate - Answer A) detect and obtain food
1. The digestive system of most animals is lined with cells through which nutrients are
absorbed. What is the embryonic origin of these cells?
A) ectoderm
B) endoderm
C) mesoderm - Answer B) endoderm
1. Which of the following is most likely to be aquatic?
A) deposit feeder
B) fluid feeder
C) mass feeder
D) suspension feeder - Answer D) suspension feeder
1. Diverse sensory organs evolved in _________.
A) animals with cephalization
B) radially symmetric animals
C) sponges first
D) terrestrial animals, and then radiated to aquatic animals
, you, as a student of biology, decide to survey them (with the aid of the Insta-Lab Portable
Laboratory you brought along in your suitcase). You select three organisms and observe them in
detail, making the notations found in the figure below. Which organism would you classify as an
animal?
A) organism A
B) organism B
C) organism C - Answer C) organism C
1. Most fish deposit fertilized eggs, but some sharks keep the fertilized egg inside the female
until she gives birth to a relatively well-developed pup. These sharks would thus be
characterized as ________.
A) livebearing
B) ovoviviparous
C) oviparous
D) viviparous - Answer B) ovoviviparous
1. What reproductive trait is most associated with terrestrial (rather than aquatic)
environments?
A) Sexual reproduction
B) Internal fertilization
C) External fertilization
D) Asexual reproduction - Answer B) Internal fertilization
1. In examining an unknown animal species during its embryonic development, how can you be
sure what you are looking at is a protostome and not a deuterostome?
A) There is evidence of cephalization.
B) You see a well-developed coelom.
C) The animal is triploblastic.
D) You see a mouth develop before an anus.
E) The animal is clearly bilaterally symmetrical. - Answer D) You see a mouth develop before
an anus.
1. What is a lophophore?
A) The single opening in a species with a blind gut