1.2 Changing populations and places

The formula for natural increase is: $\text{Natural Increase (\%)}=\frac{\text{Birth Rate}-\text{Death Rate}}{10}$ Crude rates are expressed per 1,000 population, and dividing by 10 converts the per-mille difference into a percentage.

Birth rate = 28 per 1,000; death rate = 12 per 1,000. The difference is $28-12=16$ per 1,000.

$\frac{16}{10}=1.6\%$ This means the population grows by 1.6% per year through natural increase alone.

The rate of natural increase is 1.6%, consistent with a moderately high-fertility country. This is the correct answer.

We need to convert the difference between a birth rate and a death rate (both per 1,000) into a percentage rate of natural increase, using the standard formula.

16% is the raw numerical difference between the two rates (28 − 12 = 16), but it has not been divided by 10 to convert per-mille to percentage. This is a common arithmetic error, so 16% is incorrect.

0.16% results from dividing 16 by 100 rather than by 10 — an incorrect conversion factor. The formula divides by 10, not 100, so this is wrong.

2.8% is obtained by dividing the birth rate alone (28) by 10, ignoring the death rate entirely. This does not follow the natural increase formula and is therefore incorrect.

Only 1.6% correctly applies the formula: $(28-12)÷10=1.6\%$. This is the answer.

Natural increase is defined strictly as the difference between the birth rate and the death rate over a given period. It says nothing about migration. Total population change combines natural increase with net migration (immigration minus emigration).

Natural increase = births − deaths. Total population change = (births − deaths) + (immigration − emigration). A country with positive natural increase can still lose total population if net emigration is sufficiently large.

Japan has negative natural increase (deaths exceed births). However, any future net immigration could offset that decline. Equally, a high-fertility country with massive emigration might show positive natural increase but slow or negative total population growth.

The correct answer is: 'Natural increase measures births minus deaths only, while total population change also adds net migration to that figure.' This precisely captures the distinction.

The question asks which option correctly distinguishes natural increase from total population change, a fundamental conceptual distinction in population geography.

'Natural increase includes births, deaths, and net migration...' reverses the two definitions — it incorrectly attributes migration to natural increase. This is factually wrong.

'Natural increase and total population change are identical...' is incorrect. Migration matters significantly in many countries and is never included in natural increase by definition, regardless of its magnitude.

'Natural increase measures emigration minus immigration...' completely inverts the definition — natural increase has nothing to do with migration flows. This option confuses the two components.

Only the option stating that natural increase = births − deaths, and total population change adds net migration correctly defines both terms. This is the answer.