Detailed Explanation:

✅ Statement 1 – Correct: Graphene is a two-dimensional material consisting of a single layer of carbon atoms arranged in a hexagonal lattice, and it exhibits excellent electrical conductivity due to the mobility of electrons in its structure.

✅ Statement 2 – Correct: Graphene is one of the thinnest materials (only one atom thick) yet possesses extraordinary tensile strength — approximately 200 times stronger than steel — making it one of the strongest materials tested.

❌ Statement 3 – Incorrect: Graphene is composed entirely of carbon atoms, not silicon. However, it does possess high optical transparency (absorbs only ~2.3% of visible light).

✅ Statement 4 – Correct: Due to its combination of electrical conductivity, optical transparency, and flexibility, graphene is highly suitable for use as conducting electrodes in touch screens, LCDs, and organic LEDs.