A rock contains 48 milligrams of a radioactive element. After 200 years, only 12 milligrams of the element remains in the rock. What is the half-life of the element?

4.06 hc)a five-year review of threats to the southern resident orca population of the united states concluded that the top threats were prey availability, contaminants, and effects from recreational and whale watching vessels. further down the list are oil spills, disease, and effects from commercial vessels not targeting whales. how might this list be different if it were for transient whale populations, which have a larger average population size and live farther offshore in open waters? a)the transient population is more likely to be affected by contaminants. b)the transient population is less likely to be affected by whale watching vessels. c)the transient population is more likely to be affected by disease. d)the transient population is less likely to be affected by prey availability.

Which of the following is a testable hypotheses?

Natural resources are any materials that humans obtain from the earth to meet our wants and needs.