3.
4. Bandingkan takat didih helium dan argon. Terangkan.

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

During a fierce storm a large number of tall trees on an island are uprooted by the wind and die. most of the trees on the island are now short trees and produce seeds that grow into short trees. what concept is shown in this example? question 5 options: natural selection artificial selection genetic engineering gene splicing

How are fossils used to date organisms?