Answer:
It is a visual explanation of the symbols used on the map. I hope this helps
Picture below
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:
A hot ball of gas that produces energy by combining atoms into heavier atoms.
Explanation:
A star is a huge glowing ball of hot gas, mainly hydrogen and helium. Stars fuse atoms in their core to produce heat and light energy. An example of a star is the sun, which slams hydrogen atoms together under high heat and pressure resulting in a much heavier atom, a helium atom. Very heavy elements are made in massive starts when they die.
b. Original horizontality
Hope this helps!
Answer:
C. According to the land sourthern Europe in a land of large rivers and lakes, while northeastern europe is dry and arid
