Not quite as Nature Intended
Well, it's not always easy but if you have the chance to look closely when a woman is lying on her back you may see scars about an inch and a half long directly under each breast where the breast joins the chest. The silicon sac will have been inserted via this encision. These scars are normally hidden when a woman is standing up and the breasts are hanging down a bit.
In the case of professional models who are competing to have the world's biggest tits it is often obvious because the breasts look stiff and "stuck on". Remember, real big breasts flow like bags half full of water. They do not stick out like footballs.
Some breasts are augmented with pads which slip into the bra. If they are still in a box with a price label then you are fairly safe in assuming they are artificial
Not quite as Nature Intended
Almost certainly artificial
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