Currently, two extant elephant species (X and Y) are placed in the genus Loxodonta, and a third species (Z) is placed in the genus Elephas. Thus, which statement should be true?
A. Species X and Y are not related to species Z.
B. Species X and Y share a common ancestor that is still extant (in other words, not yet extinct).
C. Species X and Y are the result of artificial selection from an ancestral species Z.
D. Species X and Y share a greater number of homologies with each other than either does with species Z.
E. Species X, Y, and Z share a common ancestor, but nothing more can be claimed than this.
D. Species X and Y share a greater number of homologies with each other than either does with species Z.
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Organic compounds are distinguished by molecules that contain ________ bonded to other elements.
A. nitrogen B. hydrogen C. oxygen D. carbon
Bacteriophages are viruses that ____
a. catalyze bacterial reproduction b. attach to bacterial cells and extract bacterial DNA c. interfere with DNA replication in the cytoplasm of cells d. produce histones e. infect and copy themselves inside bacterial cells
Ribosomes are a collection of
A) small proteins that function in translation. B) proteins and tRNAs that function in transcription. C) proteins and small RNAs that function in translation. D) proteins and mRNAs that function in translation. E) mRNAs and tRNAs that function in translation.
The protozoan that causes malaria is an intracellular parasite of red blood cells (RBCs). An adaptive immune response to this parasite is problematic because
A) red blood cells do not produce MHC and, therefore, do not display the fact that they have been infected by presenting antigen. B) the parasite damages leukocytes along with RBCs. C) RBCs normally produce cytokines necessary for adaptive immune response, which this infection prevents. D) complement cannot effectively destroy RBCs. E) RBCs never enter lymphoid tissue.