Answer:
great lakes
Explanation:
Water from the melting glacier filled the basins , forming the Great Lakes.
Answer:
b. flat rotation curves in spiral galaxies
Explanation:
Dark matter accounts for majority of the matter in the universe (about 85%). It is considered to be composed of subatomic particles which are yet to be discovered. Dark matter cannot be observed because it does not emit light that can be detected. Only its gravitational effect is visible.
Astronomers when calculated the mass of the visible matter and tried to account for the observed speed of stars in the galaxy, there was a mismatch. To understand what caused this mismatch, astronomers gave name to the invisible matter as the Dark Matter.
The expected velocity of stars should decrease away from the near the center of the galaxy but a constant velocity of stars was observed that is a relatively flat rotation curve was obtained.
Thus, flat rotation curves in spiral galaxies in an evidence of Dark Matter.
Answer:
Atmospheric pressure differs in different parts of the world.
Explanation:
- This is because atmospheric pressure depends on the height of a particular location on earth.
- A number of locations on the earth are at sea level. The atmospheric pressure at sea level is 14.7 pounds per square inch.
- At higher levels (altitudes) the atmospheric pressure is lower since higher places have got less air pushing downwards compared to lower altitudes which have more air pushing down and hence, high atmospheric pressure.
Answer:
Option (D)
Explanation:
Historical geology usually refers to the study of the changes and the variation that occurs at or below the surface of the earth. In simple words, it mainly involves the study of past events. This includes the variation and evolution of different life forms that existed on earth over a time of about 3.8 billion years until the present. It basically comprises the important part of geology namely Paleoclimatology, Paleontology and Paleoseismology. This historical geology is also known as Paleogeology.
Thus, historical geology involves the biological changes that occur over a definite time.
Thus, the correct answer is option (D).
