Statement I: An alloy of lithium and magnesium is used to make aircraft plates.
Statement II: The magnesium ions are important for cell-membrane integrity.
In the light of the above statements, choose the correct answer from the options given below

We need to evaluate both statements about lithium-magnesium alloy and magnesium ions.

Statement I: "An alloy of lithium and magnesium is used to make aircraft plates."

This statement is actually about lithium-aluminium alloys, not lithium-magnesium alloys. Lithium-aluminium alloys (Al-Li alloys) are widely used in aerospace applications because they are lightweight and have high strength. While lithium-magnesium alloys do exist, they are not the standard alloys used for aircraft body/plates. So Statement I is false.

Statement II: "The magnesium ions are important for cell-membrane integrity."

Magnesium ions ($$Mg^{2+}$$) are not primarily associated with cell-membrane integrity. It is calcium ions ($$Ca^{2+}$$) that play a key role in maintaining cell-membrane integrity and stability. Magnesium ions are mainly important as cofactors in enzymatic reactions, ATP metabolism, and nucleic acid chemistry. So Statement II is also false.

Since both statements are incorrect, the correct answer is that both Statement I and Statement II are false.

Hence, the correct answer is Option B.