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.
A radioactive element with a half-life of 1,000 years, and starting mass of 20 grams, will need 2,000 years to decrease to 5 grams.
Explanation:
The radioactive elements all have a specific half-life. Each element's half-life is well known, and they are used by scientists of numerous fields as they are excellent for determining the age of a particular item, be it or organic or non-organic nature. In this case, we have a radioactive element with a half-life of 1,000 years, and starting mass of 20 grams.
The half-life basically means that half of the mass of an element is lost during a particular period of time. For the element in question we need to find out how much time will be needed for it to decrease to 5 grams. In order to get to the result, we just need to add 1,000 years on every decrease of half of the mass:
20/2 = 10
10/2 = 5
So in 1,000 years, the element in question will decrease to 10 grams, and in further 1,000 years (2,000 cumulatively) it will decrease to 5 grams.
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False. it was extremely simple. acid rain can kill.
when trees and dirt combine i think
