Answer:
Mechanical barriers — which include the skin , mucous membranes , and fluids such as tears and urine — physically block pathogens from entering the body. Chemical barriers — such as enzymes in sweat , saliva , and semen — kill pathogens on body surfaces.
That would defined having a concussion
Two identical cell because the main purpose of the cell cycle is to make two identical cell.
Answer:
through excess us of corbon(ii)oxide emitting product such as charcoal that cause global warming hence depletion of oxygen in air
