Answer:
Respiration is a process in which energy is released due to the breakdown of glucose molecules with the addition of oxygen forming carbondioxode, water and energy in the form of Adenine tri phosphate (ATP). In respiration process, carbondioxide is released in the atmosphere and oxygen is used for breakdown of food. This carbondioxide is used by the plants in the process of photosynthesis and oxygen is released in the atmosphere which is again used by animals for respiration.
Because an antibody is "made" relative to the antigen, but kept at low levels when you are exposed the first time ("primary immune response"). The second time you're exposed to the same antigen, memory cells recognize it and the body produces a high level of antibodies, and the level of antibodies usually remains higher for a longer time ("secondary immune response"). This is your basic immune response (primary and secondary).
This explains exactly why vaccines are effective to extremely effective.
Environmental functions is the correct option. Hope it helped U. If it helped you please mark as brainliest