Answer:Animals have been used in the industrialized production of human vaccines since vaccine farms were established to harvest cowpox virus from calves in the late 1800s. From that point, and through the first half of the 20th Century, most vaccines would continue to be developed with the use of animals, either by growing pathogens in live animals or by using animal cells.
Explanation:
The answer to fill in the blank would be B) aka the second option because food gives our body energy and serves as fuel to recharge to give us energy to do things.
Geosphere, biosphere, atmosphere, hydrosphere
Carbohydrate is what you are looking for