Glenn is heating water in a teakettle. the hotter water at the bottom of the kettle rises. the cooler water near the top sinks and warms. which kind of transfer of heat is this?
conduction
convection
radiation
transmission

Option (b) is the correct answer.

Explanation:

A process in which a fluid is heated then cold material (more dense) sinks at the bottom whereas hotter material (less dense) rises at the top is known as convection.

In convection, heat transfers from burner to the vessel and further it reaches to the fluid present into the vessel.

Therefore, we can conclude that the given situation represents convection as the kind of transfer of heat.

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.