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.
Uses by sources. Energy Resources is NOT the same thing as Types of energy. Types of energy means kinetic energy, chemical energy and so forth. Energy Resources is about ways of getting energy so we can generate electrical power.