Answer: D absorb from soil
Explanation: just took the test
<span>Compared with developing countries, developed countries have high birth rates. - This statement is not true.
</span><span> With the help of family planning and education, birth rates can be decreased. - This statement is true.
</span><span>If the trend of rising birth rates continues, the population will increase and natural resources will likely start becoming scarce. - This statement is true.
</span><span>When food resources disappear, it eventually leads to food security in certain regions of the world. - This statement is false.</span>
Half life formula
The number of unstable nuclei remaining after time t can be determined according to this equation:
N(t) = N(0) * 0.5^(t/T)
where:
N(t) is the remaining quantity of a substance after time t has elapsed.
N(0) is the initial quantity of this substance.
T is the half-life.
It is also possible to determine the remaining quantity of a substance using a few other parameters:
N(t) = N(0) * e^(-t/τ)
N(t) = N(0) * e^(-λt)
τ is the mean lifetime - the average amount of time a nucleus remains intact.
λ is the decay constant (rate of decay).
All three of the parameters characterizing a substance's radioactivity are related in the following way:
T = ln(2)/λ = ln(2)*τ
How to calculate the half life
Determine the initial amount of a substance. For example, N(0) = 2.5 kg.
Determine the final amount of a substance - for instance, N(t) = 2.1 kg.
Measure how long it took for that amount of material to decay. In our experiment, we observed that it took 5 minutes.
Input these values into our half life calculator. It will compute a result for you instantaneously - in this case, the half life is equal to 19.88 minutes.
If you are not certain that our calculator returned the correct result, you can always check it using the half life formula.
He found that the recessive trait such as the short plants disappeared, but only the dominent trait stayed which is tallness. When he allowed them to self pollinate, the recessive gene which is the shortness reappeared.
He studies geosphere and biosphere.
