20. 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?
Thanks
-MC
The correct answer is option A: skull, notochord, and complex organ system.
To determine the correct answer, let's first analyze the given options:
Option A: Skull, notochord, and complex organ system
Option B: Backbone, segmentation, and open circulatory system
Option C: Two pairs of jointed appendages, cephalization, and internal skeleton
Option D: Hydrostatic skeleton, bilateral symmetry, and true coelom
Now, let's break down and analyze each option:
Option A: Skull, notochord, and complex organ system
- A skull is a bony structure that protects the brain and forms the framework of the face.
- Notochord is a flexible rod-like structure found in early embryonic stages of vertebrates, which eventually develops into the vertebral column (backbone).
- A complex organ system refers to the different systems in the body, such as the respiratory, circulatory, digestive, and nervous systems.
Option B: Backbone, segmentation, and open circulatory system
- A backbone (also known as the vertebral column) is a defining characteristic of vertebrates, providing them with structural support and protecting the spinal cord.
- Segmentation refers to the division of the body into repeated segments, which can be seen in certain groups of invertebrates but is not exclusive to adult vertebrates.
- An open circulatory system is a type of circulatory system found in some invertebrates, where the blood is not confined to blood vessels.
Option C: Two pairs of jointed appendages, cephalization, and internal skeleton
- Two pairs of jointed appendages are found in certain groups of arthropods, such as insects, but not in adult vertebrates.
- Cephalization refers to the concentration of sensory organs and nervous tissue at the anterior end (head region) of the body, which is seen in some animal groups but is not exclusive to adult vertebrates.
- An internal skeleton is a characteristic of vertebrates, but the presence of two pairs of jointed appendages and cephalization is not exclusive to adult vertebrates.
Option D: Hydrostatic skeleton, bilateral symmetry, and true coelom
- A hydrostatic skeleton is a type of skeletal system found in certain invertebrates, such as worms, where the body cavity is filled with fluid for support.
- Bilateral symmetry refers to the body plan where the organism can be divided into mirrored halves along a sagittal plane, which is a characteristic of many animal groups, including both vertebrates and invertebrates.
- True coelom refers to the presence of a body cavity that is completely lined by mesoderm, which is a characteristic of many animal groups, including both vertebrates and invertebrates.
Considering all the characteristics mentioned in the options, option A is the only one that accurately represents common characteristics of adult vertebrates: a skull (protecting the brain and forming the face), a notochord (which develops into the vertebral column), and a complex organ system (comprising various systems within the body).
Therefore, the correct answer is option A: skull, notochord, and complex organ system.