Scientists Are Concerned About the Growing Problem of Dead Zones

question 31

Multiple Choice

Scientists are concerned about the growing problem of dead zones in the Gulf of Mexico, which are caused primarily by fertilizer runoff entering the Mississippi River. Which question related to this topic would most likely be studied by an environmental scientist, as opposed to an ecologist?

• A) How does the presence of fertilizers in river water affect fish populations along the river?
• B) What is the total amount of fertilizer runoff reaching the Gulf of Mexico per year?
• C) What economic incentives might be offered to farmers to encourage them to decrease fertilizer runoff?
• D) Which types of algae and bacteria undergo population explosions in the Gulf due to increased nutrient content, and during what times of year do they occur?

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Definitions:

Vitamin D

Fat-soluble vitamin produced from precursor molecules in skin exposed to ultraviolet light; increases calcium and phosphate uptake from the intestines.

Osmoreceptor Cells

Cells that detect changes in the osmotic pressure of the body fluids, contributing to the regulation of the body's water balance.

Plasma Volume

The volume of the plasma component of blood, which is the liquid part of the blood that holds the blood cells in whole blood in suspension.

Hypertension

A medical condition where the blood pressure in the arteries is persistently elevated.