"in all areas of the world, groundwater is an important source or drinking water. however, in many areas, the groundwater is being polluted, mainly by nitrates. sometimes the groundwater is so polluted, it is no longer able to be used as drinking water. what is the most likely source of the nitrate pollutants?"

Use this dichotomous key for insect identification to identify the insect shown. 1. a. insect has one pair of wings. order diptera b. insect has two pairs of wings. go to #2 2. a. front wings thicker in texture than hind wings go to #3. b. front and hind wings are same texture throughout. go to #4 3. a. front wings are short order dermaptera b. front wings cover entire abdomen order coleoptera 4. a. wings with scale on all parts of their area. order lepidoptera b. wings without scales go to #5. 5. a. hind wings smaller than front wings. order ephemeroptera b. front and hind wings nearly equal in size. order odonata the insect pictured is in the order diptera. ephemeroptera. coleoptera. odonata.

Eutrophication caused by human nutrient pollution.

The largest unit within which gene flow can readily occur is a