Specific immunity: active immunity, passive immunity, natural immunity, and artificial immunity.
3) 5* examples of white blood cells: Monocytes Lymphocytes Neutrophils Basophils Eosinophils *(There are only 5 different kinds of white blood cells, maybe your teacher made a mistake with putting 6)*
The red cells are at the bottom and the white cells are on top of the red cells
Taking steps to reduce or eliminate pollution from nonpoint sources such as streets and farms will help to maintain the ecological balance. Sewage and run-off of agricultural fertilizer can cause the rapid growth of algae in lakes and streams. The growth of algae blocks sunlight and depletes the oxygen in the water.
The Lockheed SR-71 "Blackbird" was an American strategic reconnaissance aircraft that traveled at over mach 3, or 3 times the speed of sound. The Concorde was a French passenger jet with a top speed of just over mach 2. The Bell X-1 was the first supersonic test plane and had to be dropped from a larger plane to reach altitude.
