Clues from geology and paleontology suggest that simple cells or their precursors arose about.
A. six billion years ago.
B. six million years ago.
C. four billion years ago.
D. four million years ago.
E. one million years ago.
C. four billion years ago.
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Variables that are always different between the experimental and the control groups are
(a) independent. (b) controlled. (c) dependent. (d) a and c.
In muscle and liver tissue, glucose consumed in the diet but not immediately used is stored as ____
Fill in the blank with the appropriate word.
Based on the temperature range and precipitation, the area on the accompanying figure labeled as 5 represents which of
the following biomes? a. savanna b. temperate deciduous forest c. temperate rain forest d. taiga e. tundra
Ponds have pondweeds attached to the bottom, insect larvae that feed on the pondweeds, fish that eat the insects, and birds like great blue herons that eat the fish. In this ecosystem which of the following would have the largest total biomass (all individuals of the category)?
A. large fish B. small fish C. insects D. great blue herons