No reason, that
Because of the intense pressure of the other layers beating down on the core.
Because the core is so hot the core turns from solid to liquid.
Because the weight of the crust is beating down on the core.
None of the above.
Hydrosphere and atmosphere only
Atmosphere, hydrosphere, and geosphere
Organism, population, community, ecosystem
Ecosystem, population, organism, community
Community, ecosystem, population, organism
Population, organism, ecosystem, community
Storage, transfer, conversion
Nuclear, coal, storage
The eastern coast
Tundra and marine west coast
Marine west coast and humid continental
Tundra and subarctic
Marine west coast and subarctic
Lead free gasoline extends an automobile engine's life
Allows refiners to manufacture oxygenated fuels
Lead is a toxic pollutant
Leaded gasoline can poison catalytic converters
There might not be enough food and water for everyone.
There might not be enough room to move around.
The continents might sink into the oceans.
Available to everyone.
Capable of being used for a long time.
Related to light and heat.
A coal-burning generator.
A wood-burning stove.
A gasoline-burning car.
The Industrial Revolution
The Civil War
The American Revolution
Humans consume too much oxygen, preventing other species from breathing.
Humans have been forced to destroy dangerous, violent species.
Humans re-shape their environment, putting preasure on other species.
Plants grown in the dark cannot perform the process of respiration
Sunlight is necessary for the normal growth of bean plants
Light is necessary for the germination of bean seeds
Light is necessary for proper mineral absorption by plants
Step by step instructions to complete an investigation
Information that is collected
An educated guess based on prior experiences
An explanation of an observation that must be logical and can change after more observations are made