Andrew was exposed to the chicken pox virus as a child. What happened to that virus after it crossed the blood-brain barrier and entered Andrew’s brain? a. Nothing happened at first, but the virus remained there and caused negative effects for Andrew as he got older. b. Nothing happened since the chicken pox virus cannot cross the blood-brain barrier. c. The glia in his brain engulfed the virus and then natural killer cells destroyed them both. d. Andrew’s natural killer cells were able to quickly destroy it.

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

What are some characteristics of a free enterprise economy?

Food contains a sugar called ( ), which is broken down in a process called cellular ( ). this process uses ( ) to break down food molecules and provide energy for cells. fill in the parentheses