Which is the best way to prevent infection from e. coli polluted water?

Which of the following is not a main characteristic that scientists focus on when determining which kingdom an organism belongs to

Which medullary index indicates a human hair? a. 0.653 b. 0.733 c. 0.516 d. 0.256

According to the big bang theory, after the "bang," the universe remained dark until about  300,000 yearsone billion yearsthree minutesthree billion years  later, when neutral atoms began to form.