chemical components: groups of elements
source: beginning point, supply
kinetic energy: energy of motion
to exert: to put to use, to effect
kinetic force: the strength of motion
applied: used with, connected to
statistics: information in the form of numbers, data
theory: scientific explanation
coronary arteries: tubes carrying blood from the heart
development: the process of being made or becoming
to recharge: to energize a battery
solar system: the sun and the nine planets, including the Earth
surface: the top covering or layer, the ground
atmosphere: the gaseous mass surrounding a planet, for example, the air surrounding the Earth
to sustain: to keep alive, to support
conditions: existing circumsatances
feathers: surface covering of birds
insulation: a covering to keep in warmth
temperature: the degree of heat or cold
layer: a single thickness covering the surface
to summarize: to restate briefly
high blood pressure: a health problem
community: a place or region for living