Is "may be corrosive" a base, salt or acid

An atom of lithium-7 has an equal number of(1) electrons and neutrons(2) electrons and protons(3) positrons and neutrons(4) positrons and protons

Give more examples of this type of heat transfer:

The diagram shows the relationship between scientific disciplines. the names of some scientific disciplines have been removed from the boxes. which scientific discipline belongs in the blue box? a. physics b. biology c. chemistry d. metallurgy