Some people seem to think that one can not eat all parts of an yellow or red onion plant.
I have however found recipies where one cuts up the entire green stem and uses that in the dish. There are references to the flowerstem to be very hard and by that not being "edible" but nothing about any part of the actual plant to be poisonus.
There are of course a lot of bulb plants that are poisonus, but the onion is not among those from what I have been able to find.
a bulb
The bulb of the onion does not but the leaves of the onion plant do.
underground
the onion plant stores it'd food in its bulb.
Stem (bulb)
Bulb- onion, garlic, spring onion. Root - carrot, turnip,
because it big huge like the plant cell
The onion is completely edible. The skin, though papery and edible is usually removed as is the small root at the bottom of the bulb. these two parts are less palatable and usually discarded. The bulb and leaves (green onion) are used in a large variety of ways.
No.You plant the bulb of the onion underground and it grows and when it is ready the onion will be above the ground, but the roots will still be underneath.
its a bulb
Onions grow seeds on the tops of their stalks, not inside the bulbs. Their umbels (the flower head on the top of the plant) will dry out and then you have seeds. The bulbs themselves never have seeds inside.
It is big because before leaves sprout, the bulb is the source of food because without leaves, there is no photosynthesis thus no food unless the bulb feeds the plant (which as I said before, it does). The bulb of the onion also stores energy. Hope this satisfies!