Why can't the producers in some ecosystems make an unlimited supply of organic material

Explain the source of radioactivity in uranium in earth’s crust by which it produces nuclear radiation

This class has taught you that the use of science and medicine in practical ways has become an international endeavor. one of the greatest examples of an international science accomplishment is which allows the profiling of human dna, useful not only to science but also medicine. a) forensic science b) the fbi c) the human genome project d) bioterrorism

People with one sickle cell allele are not likely to get malaria. what is this an example of?