The chorion is produced from which primary tissue layer(s)?
a. ectoderm and endoderm
b. ectoderm and mesoderm
c. endoderm and mesoderm
d. ectoderm only
e. endoderm only
B
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Which of the following is NOT a mechanism used by bacteria to condense their DNA?
A. Super coiling B. Packaging the DNA with histone proteins C. Looping of the DNA D. Increase or decrease the number of turns in the DNA E. Anchoring the DNA loops with DNA-binding proteins
The tropics are known to have greater species diversity than the temperate zones.Which explanation for this phenomenon is the LEAST convincing?
A. Seasonal variability is less in the tropics. B. Niches are narrower in the tropics. C. Fewer predators in the tropics allow more prey species to flourish. D. Greater spatial heterogeneity in the tropics creates more niches. E. The tropics have greater plant production, which supports greater overall species richness.
The bacterial ________ facilitates the process of bacterial cell division
A) nucleoid B) inclusion C) pilus D) cytoskeleton E) fimbriae
Which scientist disproved the theory of spontaneous generation?
A) Einstein B) Pauling C) Crick D) Watson E) Pasteur