What percentage of the known naturally occurring isotopes is radioactive?
What will be an ideal response?
70/339 * 100 = 20.6%
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Where does the largest amount of upwelling occur?
a. Equatorial upwelling b. Polar upwelling c. Coastal upwelling d. Mid-latitude upwelling
The only major group of species that has escaped increasing extinction threat are the primates, where less than 10% are currently threatened with extinction.
Answer the following statement true (T) or false (F)
What is the dominant type of weathering is shown in this photograph?
A. chemical weathering B. physical weathering C. hydrolysis D. debris flow E. dissolution
There appears to be a _______ of photosynthesis and respiration currently, so the remarkable atmosphere is best understood as a result of the long term _______ of organisms in the ocean and on land.
Fill in the blank(s) with the appropriate word(s).