East of South America in the Northern and Southern Hemisphere
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.
This statement is true. Soil color only reflects the amount of organic matter that is currently present in the soil. If the soil seemed to be much darker, it means that the soil has a greater amount of organic materials which makes it better.
Flood waters can be channeled to provide irrigation is true about the development of farming in Summer. The correct option among all the options that are given in the question is the last option or option "D". Without adequate amount of water, it is not possible to farm in the summer months.
