The Most Recently Discovered Phylum in the Animal Kingdom (1995)

question 36

Multiple Choice

The most recently discovered phylum in the animal kingdom (1995) is the phylum Cycliophora. It includes three species of tiny organisms that live in large numbers on the outsides of the mouthparts and appendages of lobsters. The feeding stage permanently attaches to the lobster via an adhesive disk, and collects scraps of food from its host's feeding by capturing the scraps in a current created by a ring of cilia. The body is sac-like and has a U-shaped intestine that brings the anus close to the mouth. Cycliophorans are eucoelomate, do not molt (though their host does) , and their embryos undergo spiral cleavage.
-If harboring large populations of cycliophorans neither helps nor harms their lobster hosts, then cycliophorans can be properly considered to be
1) parasites.
2) mutualists.
3) commensals.
4) symbionts.
5) endosymbionts.

• A) 1 and 4
• B) 2 and 4
• C) 3 and 4
• D) 2 and 5
• E) 3 and 5

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Definitions:

pH

A scale used to specify the acidity or basicity of an aqueous solution, where 7 is neutral, below 7 is acidic, and above 7 is basic.

L-Valine

An essential amino acid used in the biosynthesis of proteins, distinguished by its branched-chain structure.

pH

A numerical scale used to specify the acidity or alkalinity of an aqueous solution, ranging from 0 (very acidic) to 14 (very basic).

Fischer Projection

A two-dimensional representation of a three-dimensional organic molecule by projection onto a plane, used to depict configurations around chiral centers.