Which one of the following plays a major role in gas exchange in a mammalian embryo?
A) amnion
B) hypoblast
C) chorion
D) trophoblast
E) yolk sac
Answer: C) chorion
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A population of charmingly charismatic rodents, population A, lives on a small island. The population consists of 100,000 individuals. Are all individuals of A genetically identical?
A. yes B. no
The comparison between Parazoa and Eumetazoa is best described by which of the following statements?
A. Parazoa have only one kind of cell whereas Eumetazoa have many kinds. B. The various kinds of cells of Parazoa do not form permanent associations into tissues or organs whereas Eumetazoa possess true, stable tissues. C. Parazoans are only haploid, whereas eumetazoans are diploid with haploid sex cells. D. Parazoans invert during their development whereas eumetazoans do not. E. All of the choices provided are correct.
The region in a tRNA that bonds with mRNA during translation is the ____
a. anticodon b. aminoacylation site c. TATA box d. cloverleaf e. reading frame
Circle the phrase in each pair that is likely to occur more rapidly in response to an extracellular signal
A. changes in cell secretion / increased cell division B. changes in protein phosphorylation / changes in proteins being synthesized C. changes in mRNA levels / changes in membrane potential