The "eight glasses a day" rule presumes 8-oz glasses:
8 x 8 = 64 oz = 2 quarts
1 quart = 946 ml x 2 = 1892 ml
So you should drink 3.784 of those 500ml bottles of water.
Looked at another way, each of those 8oz glasses of water holds 236.5 ml, so if you drink all four 500ml bottles of water, you're drinking a little more than 8 1/2 glasses of water.
Looked at a third way, if you measure an extra half-ounce of water into each of your eight glasses, you're up to four 500ml bottles.
c.tissue - the epithelium is a kind of tissue that makes up several organs in the body.
Vitamin A comes from leafy green vegetables, orange and yellow vegetables, tomato products, fruits, and some vegetable oils. It keeps eyes and skin healthy and helps protect against infections.