Answer: The one direction where energy as heat will be initially transferred between the blocks is from block D to block A.
Step-by-step explanation:
A substance like metal box that has high temperature will have more kinetic energy between its molecules due to which there will be more number of collisions between them.
Hence, it is able to transfer its heat energy more readily ac compared to a substance with low heat energy.
As a result, in the given diagram as temperature is increasing from block A to block B so heat energy will be transferred from block D to block A.
Thus, we can conclude that one direction where energy as heat will be initially transferred between the blocks is from block D to block A.