What’s the context behind the question?
The cycle that is carried out during food chain and energy trophic level is the carbon cycle. The carbon cycle includes the giving off of the carbon dioxide of the organisms which is absorbed by plants through the stomata in aid for photosynthesis or food making. This also includes the energy loss from one organism to another until the eventual decomposition of the animal
I don't think there is a difference
The statement is once a year for women over 40 as they're more likely to develop breast cancer. Also it's once a year for all women over 18 with a family history of breast cancer as it is very rare to develop breast cancer as a child.