Molecular fossils have fallen under scrutiny by some paleobotanists that are skeptical of the conclusions being drawn from their analysis. Why do they consider molecular fossils to be problematic?
a. There is no risk of contaminating the DNA materials during handling and isolation.
b. It is considered useless for identifying plant by-products from the past because they bear no resemblance to modern counterparts.
c. The chemical materials of interest degrade rapidly when exposed to air during isolation and handling.
d. They feel we do not have the mastery of the technology tools needed to process this sort of data yet.
c. The chemical materials of interest degrade rapidly when exposed to air during isolation and handling.
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Which of the following choices best describes the relationship that exists between moisture and air temperature?
A. The moisture-holding capacity of air decreases when it is warm and increases when it is cool. B. The moisture-holding capacity of air remains the same (warm or cool) and is not related to its temperature. C. The moisture-holding capacity of air increases when it is warm and decreases when it is cool. D. The moisture-holding capacity of air decreases as the higher altitude winds of the polar regions descend onto the continents.
Aside from whatever digestion has happened before the food reaches the small intestine, the bulk of digestion takes place in the (select all correct choices):
A. duodenum. B. jejunum. C. ileum. D. colon. E. appendix.
The coefficient of relatedness of a human child to its full sibling is, on average,
A. 0.25. B. 1.5. C. 1. D. 0.5. E. 0.75.
Which sentence characterizes cancer cells?
a. Tumours formed by cancer cells remain encapsulated and grow in only one location. b. Cancer cells form tumours that strongly adhere to surrounding tissues. c. Cancer cells display uncontrolled cell division. d. Mitosis is strictly regulated in cancer cells.