A particular region is experiencing a viral epidemic. Which of the following would increase the likelihood of the epidemic becoming a pandemic? A. A vaccine is developed that prevents individuals from being infected

B. Neighboring populations have little to no immunity to the disease.

C. The infection can be spread only by direct contact from one person to another

D. The region is remote and experiences little to no tourism.

Most scientific questions are based on opinions. hypotheses. observations. experimental data.

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

Cells tend to have a relatively small and uniform size. why aren’t cells larger?