Notes: 1  When s is a string or Unicode string object the in and not in operations act like a substring test. In Python versions before 2.3, x had to be a string of length 1. 2  Values of n less than 0 are treated as 0 (which yields an empty sequence of the same type as s).
A food web describes the flow of energy and nutrients through an ecosystem, while a food chain is a linear path through a food web. Distinguish between food chains and food webs as models of energy flow in ecosystems. Organisms can be organized into trophic levels: primary producer, primary consumer, secondary consumer, and tertiary or higher-order consumer.
Types of Energy. There are two types of energy: Potential (or stored energy) Kinetic (or energy in motion) Kinetic Energy is energy in motion. Moving water and wind are examples of kinetic energy. Electricity is kinetic energy because, even though you can't see it happen, electricity involves electrons moving in a conductor. Potential Energy is stored (or latent). Energy can be stored in many ways. A gallon of gasoline or a barrel of oil contains stored energy that can be released when we burn it.