Algebra - Abstract algebra. 1  Abstract algebra extends the familiar concepts found in elementary algebra and arithmetic of numbers to more general concepts.
Choose the freshest looking lettuce for storing. Photo Credit anna1311/iStock/Getty Images. Romaine lettuce's high water content means there is no long-term preservation method suitable for making the lettuce last longer. Drying, canning and freezing all produce inedible results. For the best nutritional value, romaine lettuce is best served when it's fresh, green and crisp. Storing the lettuce in a refrigerator is the best option for preserving it, although there are a few other measures that can be taken to ensure romaine lettuce lasts as long as possible.
I've read that crisp head lettuces in the romaine or cos group are the slowest to bolt and loose leaf the quickest, but I haven't had that experience in my garden. Many gardeners, including me, have had success growing lettuce throughout the summer by planting it in a shaded spot in the garden.