Which describes one of oxygen's roles in Earth’s atmosphere? allows fuels to burn
forms clouds that produce rain
is the gas that animals exhale
is used by plants to produce food

clinically, some people often have repeated allergies, eczema and respiratory infections or other parts of the infection, in this case, in addition to some routine tests such as tests for white blood cells, immunoglobulin series, lymphocyte subsets, etc., the five immune immunoglobulin tests are also necessary.

chordata is the answer