Canals and aqueducts allow humans to transport people and goods from one place to another place.
<h3>What are Canals and aqueducts?</h3>
A canal is a man-made waterway that link up two bodies of water and allows boats and ships to travel between them.
Aqueducts are water-conducting constructions that carry a stream of water over a hollow or valley.
Canals and aqueducts differ slightly in that a canal is an architectural waterway that connects one body of water to another, whereas an aqueduct is an artificial channel built to transport water from one site to another.
Therefore, oprtion d is the correct option.
Learn more about the waterways, refer to:
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Answer:
The main reason why mountains are rarely populated is because of the harsh climate that are dominating in those areas. On the other side, another important reason is that mountainous areas are not fertile enough and people are not able to grow crops. Lack of resources therefore is obliging people to move from the mountains to lower terrains.
Explanation:
Because of the mentioned reasons most of the people since the beginning of civilization were inhabiting river valleys and the areas that have better climate.
For example, Chinese civilization developed in the valley of Yangtze and Huang He and not Himalayas.
Snowshoe hare is the primary food of the lynx. The population cycles of these two species are closely linked.
When hares are plentiful, lynx eat little else and take about two hares every three days.
Lynx prey upon mice, voles, squirrels, grouse, ptarmigan and carrion when hares are scarce. These food sources often do not meet the lynx's nutritional needs. Some lynx cannot maintain their body fat reserves on this type of diet and become more vulnerable to starvation or predation. Other lynx manage to remain healthy by using alternative prey and food sources when the hare population is low. When snowshoe hares are scarce, many lynx leave their home range in search of food.
Hare populations across most of the boreal forest experience dramatic fluctuations in a cycle that lasts 8-11 years. At the peak of the cycle, snowshoe hares can reach a density of up to 1500 animals per km2. The habitat cannot support this many animals. As predation increases and starvation sets in, the population starts to decline. Continued predation due to high populations of lynx and other predators increases the hare population decline.
When the hare population reaches a low level, it stabilizes, for several years. The food plants slowly recover and the hare population starts to increase again. Since hares have several litters each year, the hare population increases rapidly. After a year or two at high densities, the hare cycle repeats itself.
The lynx population decline follows the snowshoe hare population crash after a lag of one to two years. As hare numbers start to decline, lynx continue to eat well because they can easily catch the starving hares.
When hares become scarce, lynx numbers also decline. Their lack of fat reserves makes them less able to live through starvation and cold temperatures. Food shortages also cause behavioural changes such as increased roaming and loss of caution. This increases their vulnerability to predation.
Malnourishment has the most significant effect upon lynx reproduction and population levels. When females are in poor condition, fewer breed and not all of those bred produce litters. Litters are smaller, and most, if not all, of the few kittens born die soon after birth. This means that for a period of three to five years, few or no kittens survive to adulthood. Studies have shown the level of kittens in a lynx population may be zero at the population low and as high as 60 percent when t numbers increase. Low lynx population levels last for three or four years. When hares become plentiful again, the lynx population begins to increase as well.
The highs and lows of the lynx population cycle do not occur at the same time across the NWT. For example, in the early 1990s, lynx numbers peaked two years later in northwestern NWT than in the southwestern NWT.
Answer: Adiabatic temperature gradient is the rate of change in temperature due to pressure under adiabatic conditions.
Explanation:
The rate of change of temperature due to pressure under adiabatic conditions is referred to as adiabatic temperature gradient.
In practice, since in the sea the pressure changes can be considered proportional to depth changes, the adiabatic temperature gradient is usually given as rate of change per unit depth, instead of per unit pressure and for practical purposes and calculations, the unit of depth is often chosen as 1000 m.
The natural and non-natural heat transfer influence the process of adiabatic temperature gradient.
