Explain the difference between threshold dose-response models and nonthreshold dose-response models.

What will be an ideal response?


With the threshold dose-response model, a certain level of exposure to the chemical must be reached before any detectable harmful effects occur. With the nonthreshold model, any dosage of a toxic chemical causes harm that increases with the dosage.

Environmental & Atmospheric Sciences

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Using the stereogram, describe the location of an apparent overhanging cliff. M32

The question is based on Figure 32-3, a black-and-white stereogram, and color Maps T-20a and T-20b (in the back of the Lab Manual). These maps show the entrenched meanders of the Green River near Canyonlands National Park, Utah. A larger portion of this region is shown in color Map T-7 in the back of the Lab Manual. Begin by looking at the flat-topped, half-circle-shaped hill about 4 centimeters (1.5 inches) from the bottom of the stereogram. What will be an ideal response?

Environmental & Atmospheric Sciences

Any solution with a pH of greater than 7.0 is acidic.

a. true b. false

Environmental & Atmospheric Sciences

Which plate does the westward-moving South American Plate encounter in South America??

A) ?Cocos plate B) ?Juan De Fuca plate C) ?Farallon plate D) ?Nazca plate

Environmental & Atmospheric Sciences

Which biome is characterized by permafrost?

A) Tundra B) High latitude temperate forests C) Cold deserts D) High latitude coniferous forests

Environmental & Atmospheric Sciences