Carl studies the kaska indians of northwestern canada and the pygmies of central africa, two societies that even today rely on simple tools to kill animals and collect vegetation for food. he studies societies.

He studies "hunting and gathering" societies.

Hunting and gathering societies are societies that depend essentially or only on chasing wild creatures, angling, and assembling wild natural products, berries, nuts, and vegetables to help their eating regimen. Until the point that people started to train plants and creatures around ten thousand years back, every single human culture were seeker gatherers. Today, just a minor portion of the world's populaces bolster themselves in this way, and they survive just in segregated, ungracious regions, for example, deserts, the solidified tundra, and thick rain forests.

answer; proximity;

question - in 1827, john walker, a druggist in a small english town, tipped a splint with sulphur, chlorate of potash, and sulphid of antimony, and rubbed it on sandpaper, and it burst into flame. the druggist had discovered the first friction-chemical match, the kind we use to-day. it is called friction-chemical because it is made by mixing certain chemicals together and rubbing them. although walker's match did not require the bottle of acid, nevertheless it was not a good one. it could be lighted only by hard rubbing, and it sputtered and threw fire in all directions. in a few years, however, phosphorus was substituted on the tip for antimony, and the change worked wonders. the match could now be lighted with very little rubbing, and it was no longer necessary to have sandpaper upon which to rub it. it would ignite when rubbed on any dry surface, and there was no longer any sputtering. this was the phosphorus match, the match with which we are so familiar. according the paragraph what was the benefit of the new phosphorus match? it burst into flame when rubbed on sandpaper. it was made by mixing chemicals. it could be ignited on any dry surface. it threw fire in all directions.

answer - matches required natural chemicals