An environmental change is occurring due to continents shifting and moving to different parts of the earth’s surface is a long term change due to tectonic plates movements. if this happends for the continously then there will be different sesonal changes .
It's c because Atoms contain three sub-atomic particles called protons, neutrons and electrons. The protons and neutrons are found in the nucleus at the centre of the atom.
They are accepted as true until they are proven false. Once a theory has been tested and it is wrong, then it is no longer true.
Answer:
a. 8.1 milligrams
b. 40.07 hours
c. 8.859 milligrams
Explanation:
If a person takes a prescribed dose of 10 milligrams of Valium, the amount of Valium in that person's bloodstream at any time can be modeled by

Where A(t) = amount of Valium remaining in the blood after t hours
t = time or duration after the drug is taken
a. we have to calculate the amount of drug remaining in the bloodstream after 12 hours


= 10×0.81253
= 8.1 milligrams
b. In this part we have to calculate the time when A(t) = 5 milligrams


0.5 = 
Now we take natural log on both the sides of the equation.
ln(0.5) = ln(
-0.69314 = -0.0173t
t = 
t = 40.0658
≈ 40.07 hours
c. In this part we have to calculate the rate, by which amount of drug will decay in the bloodstream after 7 hours.


= 10×0.8859
= 8.859 milligrams