Answer: is constant
Explanation:
In order to analyze the velocity of the stars within a galaxy, the <u>galaxy rotation curves</u> (developed by the American astronomer Vera Rubin) are used. These graphs are elaborated as a scatter diagram in which the orbital velocity of the stars present in a galaxy is represented on the Y axis and the distance of these stars to the center of the galaxy on the X axis.
Thanks to this diagram, it has been possible to observe a characteristic behavior in the rotation speed of the stars (and gas) present in the galaxies, which differs from the rules of the orbital movement of the planetary systems postulated by Newton and Kepler.
This means that in these galaxy rotation curves it has been observed that the rotation speed of stars and gas is "constant", regardless of the distance to the center of the galaxy. This discrepancy and these results were then used to demonstrate the existence of dark matter in the universe.
Answer:
Humans require water for survival, so they tend to settle near areas with access to large amounts of water. Rainfall and water bodies such as rivers and lakes provide humans with clean water for drinking, cleaning, agriculture and recreational activities. Pollution of water supplies and population growth depletes aquifers leading to competition and waterborne diseases, especially in developing countries.
Climate patterns around the world influence human settlements. They live in conditions that favor their lifestyles and alter their clothing and housing in accordance with climate. In addition, extreme weather leads to sparsely populated areas and limit agricultural practices; for example, harsh and cold weather favor plants that can adapt to that environment.
Land formations such as mountains and hills shape transportation routes and networks, while the movement of tectonic plates on the Earth's surface sometimes causes hazards like earthquakes that destroy habitats, displace humans and affect the availability of water.
Fertile soil carries out numerous functions such as supporting life, recycling nutrients, regulating water and providing structural support for buildings. Humans extract minerals and perform recreational activities on the soil. Infertility creates deserts and leads to the migration of settlements.
A balanced ecosystem relates to better agricultural produce and less air pollution. Provision of food, safe water and clean air improves the well-being of living organisms.
Explanation:
Below are the answers:
<span>1. Paris is southeast of London.
True
2. The majority of the Western European agriculture takes place on the Great European Plain.
True
3. Rome was a republic ruled by senators (wealthy landowners) and the people.
False
4. In the 21st century, the threat from acid deposition has actually been declining.
True
5.
The Ionian Sea is an arm of the Mediterranean Sea between western Greece and southern Italy.
True
</span>
An island is a land surrounded by a body of water. For example, Hawaii is an island because it is surrounded by the Pacific Ocean.
