seeds are considered better for the staple food then the vegetative part of the plant .why?...pls answer its urgent

Dear student,

Grains are small, hard, dry seeds harvested for human/animal consumption. After being harvested they can be stored for a long time. So they are considered more durable than other staple foods such as fruits and tubers.
Other advantages include:
Can be mechanically harvested.
Can be transported by trains or ships.
Can be stored for long periods.
Can be milled to produce flour.
Can be used to extract oil by pressing.
Economically favorable for industrial agriculture.

Regards.