Answer:
mafic and felsic.________________________
Answer:
B
. Improvements in nutrition, sanitation, and health care cause death rates to fall in stage 2 of the demographic transition
Explanation:
- The epidemiologic transition occurs in medical geography and states that the changing population patterns in terms of fertility, life expectancy, and death can lead to causes of death.
- The second stage is viewed as the age of receding pandemics that states that due to the increase in medical aid and facilities. Morality progressively declines and the average life expectancy increases from 30 to 50 years.
Answer: A higher dependency ratio is likely to reduce productivity growth. A growth in the non-productive population will diminish productive capacity and could lead to a lower long-run trend rate of economic growth.
2)
angle 1= 75
angle 4= 75
angle 5=63
3)
x=14
angle 2=80
angle 5= 80
angle 6 =36
sorry if my work is messygood luck my dear
Answer:
The age of the rock = 2800.6 million years = 2.8 billion years.
A simple method of analysis similar to Carbon dating is used to obtain the required age of the rock. Radioactive substances decay according to first order reaction kinetics. So, plugging all the required parameters into the general equation for amount of substance left in a first order decay gives us the age of the rock.
Explanation:
Half life of Uranium-235 = 700 million years (from literature)
The decay of radioactive substances follow first order reaction kinetics.
The general equation is given as
A(t) = A₀ e⁻ᵏᵗ
A(t) = Amount of radioactive substance left after a particular time = 6.25%
A₀ = initial amount of radioactive substance = 100%
t = time that has passed since the beginning = age of the rock = ?
k = decay constant
The decay constant is related to the half life (T) through the relation,
k = (In 2)/T
k = (0.693/700) = 0.00099 /million years
A(t) = A₀ e⁻ᵏᵗ
6.25 = 100 e⁻ᵏᵗ
0.0625 = e⁻ᵏᵗ
In e⁻ᵏᵗ = In 0.0625 = -2.7726
-kt = - 2.7726
t = (2.7726/0.00099) = 2800.6 million years
t = 2.8 billion years.
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