What can you see that plant is monocot or dicot

Monocots differ from dicots in four distinct structural features: leaves, stems, roots and flowers.

But, the differences start from the very beginning of the plant's life cycle: the seed. Within the seed lies the plant's embryo. Whereas monocots have one cotyledon (vein), dicots have two. This small difference at the very start of the plant's life cycle leads each plant to develop vast differences.