BYU EARTH SCIENCE FINAL PAPER 2025/2026 QUESTIONS
WITH SOLUTIONS GRADED A+
✔✔Why do scientists believe that heating from radioactive decay was greater in the
early earth than it is today? - ✔✔There were more radioactive elements, so as a result,
there was greater decay and heating
✔✔What two principal sources cause the earths internal heat? - ✔✔Radioactive decay
and residual heat
✔✔What would happen to plate motion if the earths interior suddenly cooled? - ✔✔Plate
motion would eventually stop as the earth cooled
✔✔Smaller solar system bodies like the moon show no plate tectonics activity. What do
you suppose would be the reason for this? - ✔✔Smaller objects must have cooled off,
so there is no energy source to power plate motion
✔✔Plantesimals - ✔✔Planetesimals are small objects that formed in the solar nebula
✔✔Differentiation - ✔✔Differentiation is the process of forming layers within a planet as
matter melt and separates due to differences in density. The heaviest stuff sinks to the
center, forming the core. The lightweight stuff forms the crust on the surface
✔✔Protoplanets - ✔✔Protoplanets are plant-sized objects that grew as planetesimals
collided together in the nebula
✔✔solar nebula - ✔✔The solar nebula is the cloud of dust and gas from which the solar
system formed
✔✔Why hasn't all the heat from inside of the earth escaped into outer space? - ✔✔Rock
is a poor conductor of heat. There has not been enough time for all the heat to have
escaped
✔✔Convection current - ✔✔A pattern of rising and sinking of rock material in the
asthenosphere due to uneven heating in the earth
✔✔Rifting - ✔✔Places where two plates are splitting open
✔✔Subduction - ✔✔The process of two plates smashing together, resulting in one
section being forced down beneath the other
✔✔Ocean to ocean - ✔✔Two ocean sections collide and one is subducted
, ✔✔Ocean to continent - ✔✔The ocean floor collides with a continent, which is folded up
into a mountain range while the ocean floor subducts
✔✔Continent to continent - ✔✔Two continents collide, making a mountain range with no
subduction
✔✔Diverging - ✔✔Two plates splitting apart from each other
✔✔Converging - ✔✔Two plates colliding with each other
✔✔Transform fault - ✔✔Two plates sliding past one another
✔✔Nitrogen is used to produce DNA. What else does it do for living things? - ✔✔It is
used to make proteins, fertilizers for plants growth, and DNA molecules
✔✔What is the power source that provides the energy to move water through the water
cycle? - ✔✔Heating from sunlight
✔✔Which statement below is false as it applies to the characteristics, properties, and
behavior of ocean currents?
A.) warm currents of a gyre generally flow away from the equator
B.) the rotation of the earth does not affect the current flow in the oceans
C.) the gyres of the northern hemisphere spiral clockwise and those in the south spiral
counter-clockwise
D.) cold currents of a gyre generally flow toward the equator - ✔✔B.) the rotation of the
earth does not affect current flow in oceans
✔✔Determine the energy levels in the following food chain.
Phytoplankton- Zooplankton - Herring- Pelican - ✔✔Phytoplankton (1000)
Zooplankton (100)
Herring (10)
Pelican (1)
✔✔By far the largest reservoir of the hydrosphere is...? - ✔✔Oceans
✔✔What energy source provides the power that makes ocean surface currents move
and winds blow? - ✔✔Sunlight energy
WITH SOLUTIONS GRADED A+
✔✔Why do scientists believe that heating from radioactive decay was greater in the
early earth than it is today? - ✔✔There were more radioactive elements, so as a result,
there was greater decay and heating
✔✔What two principal sources cause the earths internal heat? - ✔✔Radioactive decay
and residual heat
✔✔What would happen to plate motion if the earths interior suddenly cooled? - ✔✔Plate
motion would eventually stop as the earth cooled
✔✔Smaller solar system bodies like the moon show no plate tectonics activity. What do
you suppose would be the reason for this? - ✔✔Smaller objects must have cooled off,
so there is no energy source to power plate motion
✔✔Plantesimals - ✔✔Planetesimals are small objects that formed in the solar nebula
✔✔Differentiation - ✔✔Differentiation is the process of forming layers within a planet as
matter melt and separates due to differences in density. The heaviest stuff sinks to the
center, forming the core. The lightweight stuff forms the crust on the surface
✔✔Protoplanets - ✔✔Protoplanets are plant-sized objects that grew as planetesimals
collided together in the nebula
✔✔solar nebula - ✔✔The solar nebula is the cloud of dust and gas from which the solar
system formed
✔✔Why hasn't all the heat from inside of the earth escaped into outer space? - ✔✔Rock
is a poor conductor of heat. There has not been enough time for all the heat to have
escaped
✔✔Convection current - ✔✔A pattern of rising and sinking of rock material in the
asthenosphere due to uneven heating in the earth
✔✔Rifting - ✔✔Places where two plates are splitting open
✔✔Subduction - ✔✔The process of two plates smashing together, resulting in one
section being forced down beneath the other
✔✔Ocean to ocean - ✔✔Two ocean sections collide and one is subducted
, ✔✔Ocean to continent - ✔✔The ocean floor collides with a continent, which is folded up
into a mountain range while the ocean floor subducts
✔✔Continent to continent - ✔✔Two continents collide, making a mountain range with no
subduction
✔✔Diverging - ✔✔Two plates splitting apart from each other
✔✔Converging - ✔✔Two plates colliding with each other
✔✔Transform fault - ✔✔Two plates sliding past one another
✔✔Nitrogen is used to produce DNA. What else does it do for living things? - ✔✔It is
used to make proteins, fertilizers for plants growth, and DNA molecules
✔✔What is the power source that provides the energy to move water through the water
cycle? - ✔✔Heating from sunlight
✔✔Which statement below is false as it applies to the characteristics, properties, and
behavior of ocean currents?
A.) warm currents of a gyre generally flow away from the equator
B.) the rotation of the earth does not affect the current flow in the oceans
C.) the gyres of the northern hemisphere spiral clockwise and those in the south spiral
counter-clockwise
D.) cold currents of a gyre generally flow toward the equator - ✔✔B.) the rotation of the
earth does not affect current flow in oceans
✔✔Determine the energy levels in the following food chain.
Phytoplankton- Zooplankton - Herring- Pelican - ✔✔Phytoplankton (1000)
Zooplankton (100)
Herring (10)
Pelican (1)
✔✔By far the largest reservoir of the hydrosphere is...? - ✔✔Oceans
✔✔What energy source provides the power that makes ocean surface currents move
and winds blow? - ✔✔Sunlight energy
