Answer:
The crust broke up because of the convection currents, formed tectonic plates, and is slowly pushed on the surface until it collides with another plate and subducts.
Explanation:
This image gives us the basics of how the plate tectonics theory works. The material in the upper mantle is cooler and denser than the material in the lower mantle, so it drops down and it pushes the hotter and less dense material up. This creates a circular motion in the mantle, and this motion creates enormous pressure on the crust above it and breaks it up.
As the crust is broken up, magma is rising constantly for millions of years, so the new magma pushes the old solidified one further away. This also pushes two pieces of crust away from each other. As the crusts move away, they eventually collide with another plate, and either gradually merge with it, or a subduction zone is created. In the latter, the crust moves below another crust and into the mantle, where it gets melted and recycled.
Answer:
A human community with high population density and low economic status will have the highest birthrates.
Explanation:
A is not correct because usually, these are populations in countries that are transitioning from one political to another political model, and these populations actually tend to decline, mostly because of immigration.
B is not correct because such populations tend to have low birthrates, often even below the bar for simple replacement of the population.
C is not correct because such populations tend to live in very bad conditions, so despite having relatively high birthrates, they stagnate in their growth.
D is correct because such populations have both the numbers needed and also live in more traditional societies, leading to very high birthrates, as can be seen with Nigeria, Ethiopia, Pakistan, Indonesia, etc.
Answer:
Aztec civilization built them
Answer:
C
Explanation:
it had something that involves water and I'm sorry if I'm wrong
Answer:
<u>Most essential development in the environmental history of United States, is the conservation policies introduced by president Theodore Roosevelt</u>.
Explanation:
- The US is today organized by large environmental movements called the NGOs that exist on all national, international and local levels. The first view that reflected to take into account the environment was those president Roosevelt Who was motivated by the beauty of the landscape and the toll hunting took on the natural reserves.
- He became a conservationist in putting the issues of the environment first, he along with his advisor Gifford Pinchot gave the Newlands reclamation act in 1902 and gave federal lands for the development of natural parks and reserves.
- He then established (USFS) United states forest services, and proclaimed 18 national monuments, and established <u>51 bird life sanctuaries including game reserves.</u>
