The correct answer is B Subduction. Subduction is the process by which an oceanic plate gets dragged under another plate and is eventually destroyed in the mantle. Subduction occurs at convergent margins where two oceanic plates collide or an oceanic and Continental plate collide. Oceanic crust is made of mainly of silica and magnesium which is heavier or denser than continental crust which is composed mainly of silica and aluminium.
The subducting plate melts producing excess magma giving rise to volcanoes along these margins.
The following are the achievements of the Olmec
civilization:
1.
Water Drainage
-
This civilization was able to construct an
extensive drainage system that is made up of conduits. This was discovered by
the archaeologists in the town of San Lorenzo, the largest city of Olmec
cities. These was carved into a U type shape and covered by capstones. This was
believed to be used as aqueduct to provide water throughout the cities.
2.
Calendar system
-
It was discovered that Olmecs have their own
calendar system. They are using shells to represent numbers in their calendar which
starts with zero. This is one of the first uses of zero as starting point of a
number.
3.
Ulama
-
This is a game of the Olmecs with the objective
of knocking the ball through the hole with the use of hips. The sap of a rubber
tree was utilized to produce balls that was used before.
4.
Writing system
-
They are usually credited as one of those
civilizations to be the first to have their own writing system in America. Their
writing is mostly symbols rather than letter representation.
5.
Compass
-
They are the one to first create compass that
existed in America with the basic understanding of gravity and magnetism.
Es completamente verdadero, está en el mapa
Explanation:
Ans: Rising air near the equator.
