Tác giả: Patricia M. Adams

White blood cells, or leukocytes are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes ex …

Close to 75 million people in 39 states face some risk from earthquakes. Seismic hazards are greatest in the western United States, particularly California, Alaska, Washington, Oregon, and Hawaii. Th …