Most generally speaking, the arrows in the food webs/chains represent the flow of energy.
Most typically, the energy will flow from the Sun to the plants, and then those plants are eaten and when they are eaten the energy flows from the plants to whatever animal ate them.
Reatna. sorry may have spelling error.
Https://www.lungcancer.org/find_information/publications/163-lung_cancer_101/299-faqs
