The main reason why the tectonic plates move is the conversational currents. There is magma between the upper mantle and the asthenosphere that heats up at the upper mantle. The weight is so small that the magma rises with the help of these conversational currents. When the magma has ascended towards the asthenosphere, it has nowhere to go so the magma lies along the asthenosphere. There the magma cools down again because the asthenosphere is colder than the upper mantle, which makes the magma heavier and goes back down to the upper mantle, where the magma heats up again and everything starts all over again and so it goes on over and over again. Scientists have concluded that the earth's gravity causes two other processes that also cause the tectonic plates to move.
Ridge push - in the spreading zones, the sides of the tiles are raised and slide to the side as in a slide.
Slab pull - when a plate is pulled down by gravity in a subduction zone like an anchor.
Answer:
The Earth is constantly changing its position with the sun as the Earth tilts in relation to the sun. This creates the differences in the seasons and the annual warming and cooling cycles of the Earth’s Northern and Southern Hemispheres.
Explanation:
- When the North Pole tilts most toward the sun, the Northern Hemisphere experiences summer.
- Spring and Autumn) occur midway on the Earth’s journey from winter to summer and from summer to winter.
- On March 20 or 21 of each year, the Earth reaches the vernal equinox, which marks the arrival of Spring in the north and Autumn in the south. The autumnal equinox occurs on September 22-23 and marks the arrival of Fall in the north and Spring in the south.
- When it is Summer in the Northern Hemisphere, it is Winter in the Southern Hemisphere, and this has nothing to do with how close or far the Earth gets to or away from the Sun in its orbit. It’s all because the Earth is tilted on its axis.
Dark Matter only: detected through its gravitational attraction, has mass, most common form of mass in the halo of the Milky Way Galaxy, likely to consist of subatomic particles
Dark Energy only: inferred to exist from the measured acceleration of the universe's expansion, the proposed source of a universal repulsive force
BOTH: the universe contains more of this than it contains matter made from atoms, we do not know what it is made of
NEITHER: blocks light from stars behind it, "dark" because it emits only infrared light
Answer:
D
Explanation:
Population of North America: 579 million
Population of South America: 422.5 million
Combined = 1.1 billion
The main differences are that in a Closed System there are a limited number of nutrients, whereas in an Open System of growth there are an unlimited amount of nutrients. ... In contrast, in a Closed System Growth, dead cells remain in the same area where living cells are attempting to divide.
