Cardiac muscle undergoes fast, synchronous contractions stimulated by ion flow. Which type of cellular junction is
essential for achieving this action in cardiac muscle?
a. gap junctions
b. tight junctions
c. plasmodesmata
d. adhering junctions
e. desmosomes
ANSWER: a
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The common basilisk lizard will run across water on its hind legs in an erect position when startled by predators. This lizard has large feet and flaps of skin along its toes. What properties of water allow this lizard to walk on water?
A. Hydrogen bonds absorb heat when they break and release heat when they form. This helps to minimize temperature changes. B. The surface tension created by hydrogen bonds is greater than the weight of the lizard initially. C. Polar molecules are attracted to ions and polar compounds, making these compounds soluble. D. Hydrogen bonds hold water molecules together; many hydrogen bonds must be broken for water to evaporate.
If a cell has a 95% concentration of water in its cytoplasm and the environment surrounding the cell has a 90% concentration of water, water will flow
A. into the cell by osmosis. B. out of the cell by active transport. C. out of the cell by osmosis. D. into the cell by active transport. E. into the cell by facilitated diffusion.
If you were building a hypothesis test to determine whether or not the price elasticity of demand for your product is -3.0, which of the following would be a natural null hypothesis?
A. H0: Price Elasticity of Demand = 1 B. H0: Price Elasticity of Demand = -1 C. H0: Price Elasticity of Demand = 0 D. H0: Price Elasticity of Demand = -3.0
Clues to evolutionary relationships are provided by differences in DNA sequences resulting from ____
a. insertions only b. deletions only c. substitutions only d. both insertions and deletions e. insertions, deletions, and substitutions