Minick Rosing's analysis of microscopic globules of carbon found in rocks 3.7 billion years old showed that they were somewhat higher in 12C as opposed to 13C. This is significant because ________
A) 13C radiometrically decays into 12C, which lets us calculate the age of these rocks
B) life could not have arisen in an environment with excessive 13C
C) these carbon globules contain visible remains of cell walls and nuclei
D) living things that fix carbon preferentially incorporate 12C over 13C
E) meteorites must have brought 13C to the early Earth
D
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Extremely halophilic Archaea often form ________ in order to access ________
A) stalks / nutrients B) intracellular inclusions / elemental sulfur C) gas vesicles / oxygen D) intracellular membranes / sunlight
Which of these has never been observed in a viable human birth?
A) YO male B) XO female C) XXY male D) XXX female
The type of tissue represented by the accompanying figure is:
a. adipose tissue.
b. cardiac tissue
c. cartilage.
d. simple squamous epithelium.
e. elastic connective tissue.
Wings of birds and butterflies have similar functions, but different evolutionary origins. They are
A. physiological structures. B. analogous structures. C. phylogenetic structures. D. homologous structures.