The units of frequency are called hertz (Hz). Humans with normal hearing can hear sounds between 20 Hz and 20,000 Hz. Frequencies above 20,000 Hz are known as ultrasound
Energy flow is the flow of energy through living things within an ecosystem. All living organisms can be organized into producers and consumers, and those producers and consumers can further be organized into a food chain. Each of the levels within the food chain is a trophic level.
Radiation is energy that comes from a source and travels through space at the speed of light
Molecules must collide with sufficient energy, known as the activation energy, so that chemical bonds can break.
