What key characteristic differentiates plasma from other states of matter?

• A. Conducts electricity
• B. Requires high-purity oxygen
• C. Low temperature
• D. Low pressure

Answer: (A)

Plasma is an ionized gas containing free electrons and positive ions. Because these charged particles move around freely, plasma conducts electricity and responds to electric and magnetic fields. That ability to carry current and be influenced by fields is what sets it apart from the other states, where charges are typically bound or neutral and don’t support bulk electrical conduction under normal conditions. The presence of free charges is the defining feature, not the purity of oxygen, not necessarily high temperature, and not low pressure—these can help form plasma, but they aren’t what makes plasma unique.