Which statement best describes the fossil record? It is a complete record.
It is an incomplete record.
Most fossils are older than five billion years.
All fossils are younger than six hundred years.

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

Which of the following is an example of a tissue on the digestive system a. the stomach b. smooth muscle that lines the stomach c. nerve cells in the stomach d. enzyme molecules in the stomach

As molecules are formed from metabolism, entropy __ and the universe becomes less disordered. a. is decreased b. is increased c. moves closer to equilibrium d. is unchanged