How far deep they were dug up shows us what time period they came from so we can classify what dinosaur it is
Answer:
Explanation:
I would say to keep things hidden, Like for example the govenment tried to tell us lies a few times like they are no alines but there really are. The goverment keeps the bad stuff hidden deep down so, that the world can stay calm and at the same time keep allies with other places.
C. Gobi desert
Is located in east Asia
Answer:
a) are the sources of long-period comets.
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.
