The Following Questions Refer to the Description Below

question 89

Multiple Choice

The following questions refer to the description below.
Terry catches a ray-finned fish from the ocean and notices that attached to its flank is an equally long, snakelike organism. The attached organism has no external segmentation, no scales, a round mouth surrounded by a sucker, and two small eyes. Terry thinks it might be a marine leech, a hagfish, or a lamprey.
-Terry takes the body of the snakelike organism and slices it open along its dorsal side. If it is a hagfish, what should Terry see?

• A) a well-developed series of bony vertebrae surrounding the spinal cord
• B) a well-developed series of cartilaginous vertebrae surrounding the spinal cord
• C) a tube of cartilage (surrounding the notochord) with dorsal projections on both sides of the spinal cord
• D) a notochord, located underneath the spinal cord

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Definitions:

Chordae Tendineae

Heart strings that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart.

Mitral Valve

A valve in the heart located between the left atrium and left ventricle; it prevents the backflow of blood into the atrium.

Aortic Valve

A valve in the heart between the left ventricle and the aorta that prevents blood from flowing back into the heart.

Conducting System

A network of specialized cardiac muscle cells responsible for initiating and distributing the electrical impulses that stimulate heart contraction.