Which of the following are three common characteristics of echinoderms?

A tube feet, circulatory system, body symmetry
B marine-dwellers, endoskeletons, water-vascular system
C bilateral symmetry, ossicles, respiratory system
D mouths, protosomes, body symmetry

is it C?

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Which of the following is NOT a characteristic shared by all chordates?

A solid nerve cord
B notochord
C postanal tail
D pharyngeal pouches
A?


Members of the subphyla Urochordata and Cephalochordata are chordates although they lack

A a backbone.
B pharyngeal pouches.
C a notochord.
D an anus.
is it A?

Three common characteristics of adult vertebrates are

A skull, notochord, and complex organ system.
B backbone, segmentation, and open circulatory system.
C two pairs of jointed appendages, cephalization, and internal skeleton.
D hydrostatic skeleton, bilateral symmetry, and true coelom.

A or C?

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For the first question, the correct answer is B. To determine this, let's break down each option:

A) Tube feet, circulatory system, and body symmetry: While echinoderms do have tube feet and a water-vascular system (which acts as a circulatory system), their body symmetry is typically radial, not bilateral.

B) Marine-dwellers, endoskeletons, and water-vascular system: This option is correct. Echinoderms are marine-dwelling animals with endoskeletons made up of calcium-rich ossicles. They also have a unique water-vascular system that aids in movement and respiration.

C) Bilateral symmetry, ossicles, and respiratory system: While echinoderms do have ossicles and some species possess a respiratory system, their body symmetry is not bilateral but rather radial.

D) Mouths, protosomes, and body symmetry: Echinoderms do have mouths, but they are not protosomes (a specific type of embryonic development). Again, their body symmetry is not bilateral.

Therefore, option B is the correct answer.

For the second question, the correct answer is A. Let's evaluate each option:

A) Solid nerve cord: While it may seem like all chordates have a solid nerve cord, some chordates (such as the subphyla Urochordata and Cephalochordata) have a nerve cord that is not solid throughout its entire length. Instead, their nerve cords have a hollow region at some point.

B) Notochord: The notochord is a defining characteristic of all chordates, so it is shared by all members of the group.

C) Postanal tail: The presence of a postanal tail is another characteristic shared by all chordates.

D) Pharyngeal pouches: Similar to the notochord, the presence of pharyngeal pouches is another characteristic shared by all chordates.

Therefore, option A is the correct answer.

Lastly, for the third question, the correct answer is C. Let's examine each option:

A) Skull, notochord, and complex organ system: While adult vertebrates do have a skull and a complex organ system, they lack a notochord as it develops into the vertebral column (backbone) during their embryonic development.

B) Backbone, segmentation, and open circulatory system: This option is incorrect as not all adult vertebrates have an open circulatory system. Instead, they typically possess a closed circulatory system.

C) Two pairs of jointed appendages, cephalization, and internal skeleton: This option is incorrect as not all adult vertebrates have two pairs of jointed appendages. Additionally, while cephalization (the concentration of sensory organs in the head) is present in many vertebrates, it is not a characteristic shared by all.

D) Hydrostatic skeleton, bilateral symmetry, and true coelom: This option is incorrect as adult vertebrates do not have a hydrostatic skeleton but instead possess an internal skeleton made up of cartilage or bones.

Therefore, option C is the correct answer.