Answer and Explanation: Earth's climate has changed dramatically many times since the planet was formed 4.5 billion years ago. These changes have been triggered by the changing configuration of continents and oceans, changes in the Sun's intensity, variations in the orbit of Earth, and volcanic eruptions. Hope it helps!
Answer:
Ummmm... I think it is A?
Could u look at my most recent question and possibly help?
C. Australia is moving at about ~7 centimeters a year, which is about 67 millimeters.
Answer:
The first one in column 1 goes to the 4th one in column 2
The second one in column 1 goes to the 1st one in column 2
The third one in column 1 goes to the 3rd one in column 2
The fourth one in column 1 goes to the 2nd one in column 2
Explanation:
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.
