How many years had the civil war been going on before the battle of grettysburg

2 years

Explanation:

The civil war started on April 12, 1961 and the Battle of Gettysburg started on July 1, 1963. The civil war ended 2 years after the battle of Gettysburg.

d is the correct answer.

b is incorrect because it makes food by itself

c is incorrect because us humans don't know how to produce their own food using the sun like plants.

a is incorrect because consumers can depend on carnivores for eating food for consumers to eat the dead organism. same thing with omnivores.

buildings sir and respect