Which of the following statements about convection are true? a) all types of currents are convection currents b) convection always involves the circulation of a liquid or gas c) convection occurs between solids only at high temperatures d) convection can only occur during the process of boiling

Explanation:

Convection is defined as the process in which fluids (liquids or gases) are mixed together and heated. Then more dense (cooler) material will sink at the bottom and less dense (hotter) material will rise at the top.

This intermixing of fluids will lead to the formation of convection currents.

This means that convection process arises only between liquids or gases and also, it can occur during the process of boiling.

Thus, we can conclude that the following statements are true.

Convection always involves the circulation of a liquid or gas.Convection can only occur during the process of boiling.

CS has the smallest atomic radius because when you compare the atomic radius of elements
an element which is more right and more up in the periodic table has lower atomic radius.
more up:less electron layers
more right:more shielding effect