Tapioca pearls.

It's starch shaped into balls, then typically boiled in a mix of sugar and water to a gelatinous consistency.

Not sure what differences there are between the black and white ones though. I usually see the white ones, smaller in size, used in tapioca pudding, while the black ones are often larger and used for boba tea.

They are chewy little balls of boiled tapioca dough soaked in brown sugar.

It's just gel encased fluid, poured into other fluid. Texture is kinda like some soft berries