Grade 3
A push or pull.
Force
A path through which electric current can flow.
Circuit
The removal of trees from a large area.
Deforestation
Microscopic, one-cell-wall thick blood vessel where exchange of materials occurs between blood and body cells.
Capillary
A way of acting that an animal does not have to learn.
Instinct
A lens that is thinner in the middle and always makes objects look smaller.
Concave Lens
A living thing in an ecosystem, such as a plant, an animal, or a bacterium.
Biotic Factor
System made up of the brain and the spinal cord.
Central nervous system
The area around a magnet where its force can attract or repel.
Magnetic Field
The movement of energy from a warmer object to a cooler object.
Heat
The tissue through which food from the leaves moves throughout the rest of a plant.
Phloem
Blood is confined to the vessels as it moves through the body.
Closed circulatory system
The process in which an animal changes shape.
Metamorphosis
A wave vibrating perpendicularly to the direction that the energy moves.
Transverse Wave
The regular rise and fall of the water level along a shoreline.
Tides
The development of desert-like conditions due to human activities and/or climate change.
Desertification
All the members of a group of one type of organism in the same place.
Population
A force between surfaces that slows objects or stops them from moving.
Friction
A chunk of rock from space that travels through Earth’s atmosphere.
Meteor
A microscope that uses a magnetic field to focus a beam of electrons through an object or onto an object’s surface.
Electron Microscope
The struggle among organisms for water, food, or other resources.
Competition
The location north or south of the equator.
Latitude
The way light bounces off an object.
Reflectivity
The response of a plant to gravity.
Gravitropism
An inherited trait that makes an individual different from other members of the same family.
Variation
The release of water vapor mainly through the small openings on the underside of leaves that drives the movement of material throughout a plant.
Transpiration
The path that energy and nutrients follow among living things in an ecosystem.
Food Chain
The distance in degrees north or south of the equator.
Latitude
An imaginary line through Earth's center.
Axis
The movement of weathered material from one place to another.
Erosion
Land near a body of water that is likely to flood.
Floodplain
Specialized internal cell structure that carries out specific cell functions such as protein synthesis and energy transformation.
Organelle
The build-up of an electrical charge on a material.
Static Electricity
Standards on which a judgment or decision may be based.
Criteria
An area where molten rock from within the mantle rises close to Earth's surface.
Hot Spot
A type of air pollution; a yellow-brown haze formed mainly from automobile exhaust in the presence of sunlight.
Photochemical Smog
An organism that is introduced into a new ecosystem.
Invasive Species
A nerve that is not part of the central nervous system and receives sensory information from cells in the body.
Peripheral Nerve
Any of the patterns of stars that can be seen in the night sky from Earth.
Constellation
Global wind systems that lie between latitudes 60° N and 60° S and the poles and are characterized by cold air.
Polar Easterlies
The long-term average weather conditions that occur in a particular region.
Climate
Energy that comes from a source in the form of waves or particles.
Radiation
The path an object takes as it travels around another object.
Orbit
An increase in a material’s volume when the temperature is increased.
Thermal Expansion
Two-phase anabolic pathway in which the Sun’s light energy is converted to chemical energy for use by the cell.
Photosynthesis
An organism that cannot make its own food.
Consumer
The natural process that occurs when certain gases in the atmosphere absorb and reradiate thermal energy from the Sun.
Greenhouse Effect
Observable characteristic that is expressed as a result of an allele pair.
Phenotype