When did austria hungary declared war on serbia?

Wha industry did the refrigerated rail car impact the most

Brainliest asap!me : ) has anyone read the poem, no, love is not dead? ? i have a question about it .. : )

One drawback of voluntary trade is that it a.requires two groups to use a common language b.can make one group dependent upon another for necessary goods c.doesn't occur unless there is a shortage of goods for at least one group d.forces groups to rely on themselves to produce all the goods they need