Answer:
Explanation:
Archaeological excavations starting in the 1840s CE have revealed human settlements dating to 10,000 BCE in Mesopotamia that indicate that the fertile conditions of the land between two rivers allowed an ancient hunter-gatherer people to settle in the land, domesticate animals, and turn their attention to agriculture ...
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:
Volcanic rock, quartz, and sandstone.
Explanation:
Answer:
one year, mostly beyond earth's orbit
Explanation:
- For a comet that has a very concentric orbit which brings it quite close to the sun and is at a distance of the AU of one thus making it around one year to orbit and would spend its time mostly in the beyond the orbit of the earth. As bodies that are closer to the sun move faster
Answer:
Many new dinosaurs emerged—in great numbers. Among them were stegosaurs, brachiosaurs, allosaurs, and many others.
Explanation: