Viruses are considered non-living organisms because:
a. they contain dna
c. they contain rna
b. they cannot reproduce outside a living cell
d. they cause disease

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

Under the soviet system, the government a. controlled all forms of communication. b. allowed newspapers to print whatever they wanted. c. controlled editorials but not the reporting of news. d. encouraged access to a wide variety of news sources. select the best answer from the choices provided a b c d

Directions: read the descriptions of the four islands presented in the lesson. 1. list two new traits that each new species of rat might demonstrate as it adapts to the conditions on each island. 2. introduce one of the four new rat species to another island and describe one challenge it would encounter and one success as it adapts to its new environment.