One (1) litre of water weighs one (1) Kg, so one ml of water weighs one (1) gram.
No, milliliter is a measure of volume, and grams is a measure of mass. Only if you mean the liquid of pure water, then: 1 ml of water has a mass of 1 gram.
An American dolar bill.
1 ml of water.
1 milliliter of pure water weigh 1 gram.