A key characteristic of aquatic dead zones is . A key characteristic of aquatic dead zones is . a high concentration of urban development a low concentration of oxygen low concentrations of nitrogen and phosphorus a lack of water a low concentration of keystone species

The correct answer is "low concentration of oxygen".

Explanation:

One of the key characteristic of aquatic dead zones is its low concentration of oxygen. Aquatic dead zones are classified into this category for being hypoxic, condition that do not support the growth of most marine life. Most aquatic dead zones are in these conditions because of a high content of nutrient pollution caused by human activities.

multiplying and dividing the two decimals and the eqations by the same number of the overalls

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.