Justify the statement that the maize grain is a 'one seeded fruit'.

A fruit is the enlarged ripened ovary in which the ovarian wall forms the fruit wall and encloses the seed. The fruit protects the seed and helps in seed dispersal.
The maize grain is regarded as a 'one-seeded fruit' because the fruit wall and the seed coat are fused to form a protective layer. Such a fruit is called grain.