Assume biological substances are 90 percent water and the density of water is 1.0 ✕ 103 kg/m3.

(a) estimate the mass of a spherical cell with a diameter of 2.50 µm (volume = 4/3 π r3)

(b) estimate the mass of a fly, which can be approximated by a cylinder 3.40 mm long by 1.70 mm in diameter (volume = l π r2)

answers should be in kg

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