Given a scientific question, generate a correct answer to it.

[Q]: What is the smallest particle of an element that still has the properties of that element is called?
[A]: atom

[Q]: In living systems, diffusion of substances into and out of cells is mediated by the what membrane?
[A]: plasma

[Q]: Sulfate is used as a cleaning agent because it is acidic and soluble in what substance?
[A]:
water