Conductors and Insulators. In a conductor, electric current can flow freely, in an insulator it cannot. Metals such as copper typify conductors, while most non-metallic solids are said to be good insulators, having extremely high resistance to the flow of charge through them.onductors and Insulators. In a conductor, electric current can flow freely, in an insulator it cannot. Metals such as copper typify conductors, while most non-metallic solids are said to be good insulators, having extremely high resistance to the flow of charge through them.
Butterhead lettuce. A type of head lettuce whose botanical name is Lactuca sativa var. heirloom. Two common types are Boston and bibb lettuce. Have small, round, loosely formed heads with soft, buttery-textured leaves ranging from pale green on the outer leaves to pale yellow-green on the inner leaves.
Dark Green Veggies: Lettuce & Leafy Greens. Next to potatoes, lettuce is the second most popular veggie in the United. States. And for generations, that lettuce has been iceberg lettuce. However, while many Americans continue to build salads and top sandwiches with ice-. berg lettuce, others, like Popeye, have begun discovering the benefits of oth-.