How are messages sent in the nervous system

Which element is used in photosynthesis found in atmosphere and fixed by bacteria?

Which ideas did your answer contain? check all that apply. no food for organisms no oxygen in the atmosphere no trees or flowering plants no products based on trees or plants (building materials, medicines, fuels, fibers) no fossil fuels

What are antigens and antibodies? how are they involved in the body’s response to incompatible blood?