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.
Three perennial favorites â iceberg, romaine and green leaf lettuces â thatâs whatâs in our Lettuce Trio Â® .For those who like to mix things up a little â or maybe your family favors iceberg, and youâre ready to try something just a little different â Lettuce Trio is a great place to start!hree perennial favorites â iceberg, romaine and green leaf lettuces â thatâs whatâs in our Lettuce Trio Â® .