Oxygen moving from the bloodstream into a cell down a concentration gradient is a form of what?

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

Land conservation is a worldwide priority. there are several methods to prevent the loss of land due to a variety of reasons. which method is not a way to conserve land? a) sea walls b) rainwater harvesting c) limits on clear cuts of forests d) cut and burn methods of clearing land

How energy move through ecosystem ?