Government agencies carefully monitor water quality and its effect on wetlands (reference: environmental protection agency wetland report epa 832-r-93-005). of particular concern is the concentration of nitrogen in water draining from fertilized lands. too much nitrogen can kill fish and wildlife. twenty-eight samples of water were taken at random from a lake. the nitrogen concentration (milligrams of nitrogen per liter of water) was determined for each sample.

The question letters are:                                  

a) Identify the variable.

b) is the variable quantitatie or qualitative?

c) What is the implied population?

a) Nitrogen concentration

b) Quantitative

c) The entire lake

Explanation:

The samples are studied to determine the variable, which is the physical or chemical property that indicates something about the placed studied. If the variable only indicates the presence or absence of a substance it's called qualitative, and if it gives value and determines how much of the substance is ar the sample, it's quantitative.

So, the study wants to know if the nitrogen concentration is too high, so it needs nitrogen concentration as a variable. The variable will give the amount of nitrogen, thus it's quantitative. The samples were got in the lake, so, the implied population by the study is the entire lake.

the molecules move in straight line until they collide with each other or with the walls of the container. collisions are perfectly elastic; when two molecules collide, they change their directions and kinetic energies, but the total kinetic energy is conserved.

explanation: