24. History of Life on Earth
History of Life on Earth
Multiple Choice
Multiple ChoicePrior to the Cambrian explosion, most animals were small and soft-bodied. What development appears to have spurred adaptations such as sharp spines, claws, and body armor (shells)?
A
Increase in oxygen concentration in the atmosphere
B
Aerobic respiration
C
Radial symmetry
D
Filter feeding
E
Predation
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