The beginning of the Cambrian period marks an important event in animal evolution — the appearance of organisms with ________.
A) wings
B) cells
C) hard parts
D) vertebrae
E) none of the above
Ans: C) hard parts
You might also like to view...
The prediction phase of forecasting
A) involves using the governing equations. B) applies equations only once. C) is not run on a computer. D) is used only in short-term forecasts.
North America is NOT a region that is affected by desertification
Indicate whether the statement is true or false
Describe the eolian processes of deflation and abrasion
What will be an ideal response?
Which of the following statements about underground contaminants is false?
a. Degradable organic wastes do not decompose as rapidly underground as on the surface. b. There is little dissolved oxygen to aid in degradation of wastes. c. Waste products are diluted and dispersed quickly in underground aquifers. d. It can take hundreds to thousands of years for contaminated groundwater to cleanse itself of degradable wastes. e. In some coastal areas, groundwater has been contaminated by saltwater intrusion.