Answer:
Transitional Stage
Explanation:
Declining death rates due to increased food production and improved medical care while birth rates remain high is characteristic of the TRANSITIONAL stage of the demographic transition.
The human population continues to increase at this point because of rising birth rates and declining death rates. The death rates are declining as there are changes in the economy and social conditions as the country transforms into an developed society.
The theory of demographic change is a theoretical explanation of rising mortality, fertility, and rates of growth as populations shift from one demographic system to another.
Answer:
B and C
Explanation:
B. In a given rock sample, the amount of Silicon-32 isotopes gets divided in half about every 170yrs.
This is the concept of half-life. Half life is the time take for half of a radioactive isotope to disintegrate. The shorter the half life the faster the isotope disintegrates.
From the question, we were told that it would take 170yrs for half of the isotope of Silicon to disintegrate to Phosphorus. This is the half life.
C. The half life can be used to determine the amount of Si-32 that has decayed from the time closure temperature was reached.
The closure temperature is very important in radioactivity. It is the temperature at which a system has cooled and there is no resulting disintegration of parent and daughter isotopes.
From first order kinetics, we know that the rate at which radioactive elements decay at any time is directly proportional to the number of radioactive atoms present. A knowledge of the half life helps to figure out the number of atoms that has decayed in time.
You need to include the drawing to help u
