If the heritability of a particular trait is found to be 60 percent, then by definition the other 40 percent is due to .

Environment.

Explanation:

Heredity may be defined as the transfer of characters from the parents to their offspring.  DNA is the heredity material of the organism that determines the genotype and phenotype of the organisms.

The environment as well as the heredity factor plays an important role in the characteristic of the organisms. The heritability is 60% this means the remaining difference might arise due to the effect of the environment on the particular trait.

Thus, the answer is environment.  

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