Which has the greater mass1 kg lead or 1 kg feathers?

The mass is the same.

Explanation:

The problem is talking about the mass, and remember that Kg is a unit of mass. For that, 1 kg of any substance is the same as 1 kg for other substance, so both meassure the same.

plasma is the state of matter where the substance is ionized and has no definite shape or volume. the fact of being ionized makes the substance a good electrical conductor.

it's all four options.