Which of Mendel's laws or principles explains that traits are passed from parents to offspring individually instead of as pairs, groups, or sets?

The law of independent assortment explains that different traits are inherited independently of one another, rather than being passed on together as a fixed group. The law of segregation instead describes how the two alleles for a single trait separate during the formation of sex cells. Therefore, the correct choice is the law of independent assortment.

AI-written and checked against the verified answer.