Which areas of the world are not considered biomes? * a. freshwater ecosystems b. marine ecosystems c. mountains and ice d. none of the above

Why might surface mining be less risky for miners than underground mining? a. surface miners can become trapped in a collapsed mine. b. surface miners work in dusty, enclosed areas. c. surface miners work aboveground. d. surface miners use elevators to enter mines.

Elements and compounds are pure substances that cannot be broken down physically into a simpler substance. a physical change doesn’t break the bonds between atoms of a substance or form new ones. compounds can be broken down by a chemical change. a chemical change breaks chemical bonds and/or forms new ones between atoms of a substance. what simple substance would a compound break into? the basic elements that make it up! for example, if you passed a very strong electric current through water you’d break the chemical bonds in water and be left with oxygen and hydrogen. which of the following is an example of a chemical change? a separating water into different glasses b breaking frozen ice cubes with a hammer c running an electric current through water d boiling water to evaporate it on a stove

Diagram of the evolution of land plants?