All of the following animals have placentas EXCEPT
a. kangaroos.
b. opposums.
c. echidnas.
d. koalas.
e. wombats.
C
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Blood agar is both a differential and enriched medium.
Answer the following statement true (T) or false (F)
Prions are of significance because they cause infections of
A. plants. B. prokaryotes. C. domestic animals and humans. D. fungi.
The Crenarchaeota, Thaumarchaeota, and Euryarchaeota are ________.
A. now classified with the bacteria based on genomic sequence analysis B. very closely related based on 16S rRNA comparisons C. photosynthetic Archaea D. the three phyla of the Archaea
A 1-year-old boy is evaluated for a suspected immune deficiency. He has a history since birth of eczema, recurrent rashes, and diarrhea. His white blood cell count (WBC) count is 6.75/uL (normal values: 5.0-10.8 x 103 uL) with a normal differential. Platelet count is 35,000 (normal values: 150,000- 350,000/uL), and the platelets are small. His IgG is 750 mg/dL (normal values: 600-1,500 mg/dL). IgM is 30 mg/dL (normal values; 75-150 mg/dL). IgA is 475 mg/dL (normal values: 50-125 mg/dL). IgE is 750 mg/dL (10-50 mg/dL). The boy's blood is typed as O-positive, and he does not have anti-A or anti-B antibodies. Flow cytometry performed on his blood shows 11% CD19 (normal values: 5%-20%) and 50% CD3 cells (normal values: 60%-80%) with a normal ratio of CD4:CD8. T-cell function tests are
abnormal. This boy most likely has: A. Bruton's tyrosine kinase deficiency. B. Wiskott-Aldrich syndrome. C. DiGeorge anomaly. D. ataxia telangiectasia.