What is the difference between parents and the mergeset in Kaspa?

In Kaspa's blockDAG, parents and the mergeset play different roles: parents determine the structure of the graph, while the mergeset determines which blocks actually count toward consensus. When a new block is created, it references previous blocks as its parents, and those references build the overall shape of the blockDAG. However, not every parent block ends up in the mergeset — the selected group of blocks that feed into consensus calculations like blue score and blue work. A block can be a structural parent and still be excluded from consensus if it ends up colored red in the mergeset. This distinction matters for beginners because it explains why Kaspa can safely absorb parallel blocks without breaking agreement across the network.