To be effective, a pot holder should have low viscosity conductivity malleability density

Option (b) is the correct answer.

Explanation:

A pot holder should be such that when a pot is heated then its holder should not get heated because only then we will be able to hold it with our hand. Otherwise our hand will burn if pot handler will have high conductivity.

Whereas viscosity is the property of a fluid which resists its flow.

Malleability is the property of a metal in which the metal can be drawn into thin sheets.

Density is the mass per unit volume of an object.

Thus, we can conclude that to be effective, a pot holder should have low conductivity.

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).