Why are protozoa significant? select all that apply.
protozoa contaminate the water supply.
protozoa do not contribute to a food chain.
some protozoa clean polluted water.
some protozoa are parasitic and cause diseases like malaria.
protozoa have an important role in the food chain.

The many stone tools, fragmentary animal bones, and teeth found at gran dolina, spain, indicate that hominids there? a. processed and consumed animals and other hominids. b. did not differ appreciably from earlier asian homo erectus. c. were similar to later homo sapiens. d. none of the above