Earth's Structure
What is the dense central part of Earth made of nickel and iron?
The core
Which type of boundary creates mid-ocean ridges?
Divergent
Soil is a mix of geologic and _______ components.
Organic
Which horizon contains plant roots, leaves, and organic material?
O Horizon
Which soil particle is largest: sand, silt, or clay?
Sand
What is the flexible, semi-molten layer beneath the lithosphere?
The Asthenosphere
Which boundary causes subduction zones and volcanic arcs?
Convergent
What is the main organic part of soil formed from broken-down biomass?
Humus
Which horizon is also called “topsoil”?
A Horizon
Loam is an ideal soil mixture of what three components?
Sand, silt, and clay
Which layer includes tectonic plates?
The Lithosphere
Which type of boundary causes earthquakes when plates slide past each other?
Transform
Name the three types of weathering that breaks down rock.
Physical, Biological, and Chemical
Which horizon is mostly minerals with little organic matter?
B Horizon (Subsoil)
What is the relationship between permeability and water-holding capacity?
Inverse relationship
Which part of Earth slowly circulates due to heat from the core?
The Mantle (Magma layer)
What mountain range formed when two continental plates collided?
The Himalayas
What four factors influence soil formation?
Parent material, topography, climate, organisms
Which horizon is least weathered and closest to bedrock?
C Horizon
What soil property is measured using pH strips?
Acidity/alkalinity (pH)
What is the very outermost layer of the lithosphere?
The Crust
What “ring” marks the zone of frequent earthquakes and volcanoes around the Pacific Plate?
The Ring of Fire
What is the process of moving weathered material from one place to another?
Erosion
Which horizon contains the most biological activity?
A Horizon
Which type of soil holds nutrients best due to its negative charge?
Clay