A geography question in the first year of high school, asking for explanation

c, the sharp decline in the number of people in the country A should be the beginning of the 20th century; b. The fastest growth of people in country B should be the end of the 21st century; The birth rate of country D is greater than the death rate, while the birth rate of country A is less than the death rate, indicating that country A has a high degree of aging and corresponds to c.

Correct Answer: Explanation of Answer: In the middle of the nineteenth century, after 1850, the state-mandated birth rate was higher than the death rate, and the population did not decrease significantly.

In countries B and B, the fastest population growth during this period should be the largest difference in the annual birth rate minus the death rate, which is probably 1975, as you can see from the figure.

c, since the beginning of the 19th century, the developed countries of Europe and the United States, due to the gradual start of the industrial revolution, the demand for labor has been growing, and has begun to show a positive growth trend, because in the second half of the 19th century, the population in the second half of the 19th century. Before the year 2000, the industrial revolution in most European countries had been completed and entered the ranks of developed countries, and the natural growth rate of population naturally declined, accompanied by reverse urbanization

d, b is the clear state of population growth in developing countries (the beginning of rapid population growth in World War II); The population of a country, developed countries. Under the conditions of the aging of the world's population, in developed countries than in developing countries, this ratio in the overall proportion of the aging population of the aging population in developing countries, now economic development, objectively need labor.

The answer is c, the birth rate is the proportion of the newly born population to the total population, the death rate is the proportion of the number of deaths to the total population, population growth and the birth rate are closely related to the mortality rate, if the birth rate is greater than the death rate, it means that the population growth is fast, if it is close, it means that the population growth is slow, if the birth rate is lower than the death rate, it means that the population is negative. First of all, in the middle of the 19th century, it was 1850, and the birth rate and death rate in country A were declining, but the birth rate was still higher than the death rate. It shows that the population is growing, not decreasing.

In addition, the birth rate and death rate of country B are very close in the year, indicating that the population growth rate is relatively slow. c. Population growth in developed European countries is slow, sometimes even negative. In 2000, the birth rate was lower than the death rate, and the population growth was negative, which was in line with the population trend of developed countries.

d Only a relatively fast population growth can solve the problem of aging, that is, the proportion of the elderly population to the total population is high, that is, only when the birth rate is much higher than the death rate, there will be no aging, and the aging of A is more serious, because the population has already experienced negative growth.

d, in the second half of the 20th century, the mortality rate of B is declining linearly, the mortality rate is decreasing due to the improvement of medical conditions, the population of family planning is decreasing, the current population is aging, and the birth rate of A mortality rate is not much different in modern times.

Your answer to the first question is already wrong, it's the winter solstice.

(1) Winter solstice day December 22.

2) The area south of the Tropic of Cancer The area north of the Tropic of Cancer.

3）c a 8（4）12 8 6

The solar altitude angle on the arc of ABC is 0°, which shows that ABC is the morning and dusk line.

At this time, someone was observing the North Star somewhere 3 885 km due south of place B, and it was known that the meridian where place B is located at 80°W is the central meridian of the night, and the local time is 0 o'clock.

The meridian 140°W where A is located is the dusk line, and the local time is 20 o'clock at this time, that is, the sunset time of place A is 20 o'clock.

then a sunrise time is 4 o'clock.

Other conditions: 3 885 km from a place directly south of B, it can be known that the distance from B: 3885 111=35°

Observing the North Star, the average elevation angle of the observed North Star is 42°, and the geographical latitude of a certain place can be known to be 42°. then ground b is 42+35=77°;

It can be seen that the range of the polar day and night phenomenon in the Northern Hemisphere at this time is 90-77=13°.

(1) If the elevation angle of the North Star is 42° from the south of place B, the local latitude is also 42°;

2) If the distance between the place and the place B is 3885km, the latitude distance is 3885 111=35°, and the latitude of place B is 42+35=77°;

3) It is inferred that the direct point of the sun is at 13° south latitude or north latitude at this time;

4) According to the longitude of the three points of ABC on the map is the degree of west longitude, the latitude of place B is 77° north latitude, then A and C are 77-60 = 17°;

5) If the direct point of the sun is at 13° north latitude, then the sunset in place A is at this time, and the place on the meridian of place B is 12 o'clock at night, you can find the time zone difference between the two places in A, the time zone between A and the time of the day before, the time of A is in the West 9 District, and the place B is in the West 5 District, then the sunset time of A is 12-(9-5) = 8 o'clock (afternoon) that is, 20 o'clock, and the sunrise time should be calculated;

6) If the direct point of the sun is at 13° south latitude, then the sunrise is at this time in place A, and the place on the meridian of place B is 12 o'clock at noon, then the time zone difference between the two places in AB is 4 hours, and the sunrise time in place A is 12-4=8 o'clock (morning).

First of all, the observation of the North Star can only be observed in the Northern Hemisphere, if point B can be observed beyond 35 degrees of latitude to the south (latitude was 111km at one point), then this map must be in the Northern Hemisphere, the elevation angle of the North Star is observed 35 degrees south of point B, and the elevation angle of Polaris is 42 degrees to the south, then point B is 77 degrees north latitude. Polaris can only be observed at night, so the area between the ABCs is night. According to the difference of 140-20 degrees, A-C crosses the night range of 120 degrees, that is, 8 hours, then the time of sunrise is.

3.Select D

Item a. The linear velocity is the same at the same latitude, but it is obviously different at different latitudes, and O and PQM are not at the same latitude, so option A is wrong.

Item b. There is a top view of the Earth's rotation direction "South and North North". The diagram is moving clockwise, so it is the Southern Hemisphere. Geostrophic deflection force "south, left, north, right" The geostrophic deflection force in the southern hemisphere should be to the left, so the erosion of the left bank of the river in the southern hemisphere should be greater Item b is wrong.

Item C Item D.

OP is the meridian at 0 local time, and the date of the non-shaded part is known to be different from the shaded part, so it can be known that OP and ON are 180° meridian or the meridian at 0 time. As can be seen from the figure, OP happens to be the meridian that bisects the day (night) hemisphere, so it can be seen that OP is the meridian at 12 o'clock or 0 o'clock local time. Judging from the above two points, OP is the meridian at 0 o'clock in local time.

So on is the morning line om is the dusk line, so d is correct c false second question I will give you a perfect answer or you ask and I will do it for you.