This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
If the first block is on a floor or a table, and the second block is kept on the first block, we have a total of 4 forces.

Normal reaction of floor or table on first block, weight of first block,
normal reaction of first block on second block and weight of second block.

between the two blocks at the surface of contact: two forces.