The "Cambrian explosion" refers to
A. the mass extinction of dinosaurs.
B. the origination of all major phyla of animals.
C. the development of the first true cell.
D. the origination of life.
E. the creation of Earth.
Answer: B. the origination of all major phyla of animals.
You might also like to view...
Shortly after ingesting a big plate of carbohydrate-rich pasta, you measure your blood's hormone levels. What results would you expect, compared to before the meal?
A) high insulin, low glucagon B) low insulin, low glucagon C) high insulin, high glucagon D) low insulin, high glucagon E) low insulin, no change in glucagon
A protein that has had its physical and chemical properties changed is said to be
A. denatured. B. dysfunctional. C. hydrolyzed. D. saturated.
Figure 23.3
Refer to the accompanying figure. What fungal structure is comprised of a mass of threadlike strands of cells, attached one to the other?
A. mycelium B. protistans C. mycorrhizae D. stolons E. rhizoids
Which phase of contraction links the action potential in the sarcolemma to the activation of the myofilament?