How does heat transfer takes place between any two systems?

Explanation:

For transfer of heat between any two substances or matter can be occurred by conduction or convection process.

Conduction is a process in which two objects of different temperature are placed in contact with each other. Therefore, heat transfers from hotter object to colder object until the temperature of both objects becomes equal.

For example, a metal spoon placed in a hot cup of tea.

Convection is a process in which a fluid generally liquid or gas is heated and denser material (colder) sinks at the bottom whereas less denser material (hotter) rises at the top. This causes conventional currents in the fluid.

For example, heating rice in a pot full of water.

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."

the answer is minerals.