3 ms·
Could there be any confounding factors in that relationship? There were a good number of vaccines invented over the last hundreds years.
by xapata 9y ago
Could there be any confounding factors in that relationship? There were a good number of vaccines invented over the last hundreds years.
- valuearb 9y agoObviously it's to the only factor, but the ICE gave us the ability to mass farm food and products and deliver them throughout an enormous country. It directly influenced where people could live, and how well they lived.