Groundwater contamination occurs when man-made products such as gasoline, oil, road salts and chemicals get into the groundwater and cause it to become unsafe and unfit for human use. ... Road salt, toxic substances from mining sites, and used motor oil also may seep into groundwater.
(Didn’t apply the statements so I answered the question hope I helped!)
Mark as brainliest please!~
Topographic maps use contour lines to show elevation.
Topographic maps, often called "topo maps," feature contour lines to portray the shape and elevation of the land.
Contour lines (lines of equal elevation) that are close together indicate steep terrain, while lines that are far apart indicate flat terrain.
Such maps also usually portray both natural and artificial features. They show and name natural land formations such as mountains, valleys, plains, lakes, rivers and vegetation. They also identify particular man made features such as roads, boundaries, transmission lines and major buildings.
Answer:
The current amount of the Potassium-40 sample is approximately 37.521 grams.
Explanation:
The amount of the sample of the radioactive isotope decays exponentially in time, the amount of mass of the sample as a function of time (
), in grams, is described below:
(1)
Where:
- Initial mass, in grams.
- Time, in years.
- Time constant, in years.
The time constant can be found from half life (
), in years, described in statement:
(2)
If we know that 
, 
and 
, then the current amount of the sample is:
The current amount of the Potassium-40 sample is approximately 37.521 grams.
The answer is a. I'm guessing cause I can't see the question all the way
Rainwater and rivers/streams
