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The immune system is a complex network of cells and proteins that defends the body against infection. The immune system keeps a record of every germ (microbe) it has ever defeated so it can recognise and destroy the microbe quickly if it enters the body again.
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Answer:
The major bones of the arms (humerus, radius, and ulna) and the legs (the femur, tibia, and fibula) are all long bones. The flat bones include the scapula (wingbone), the ribs, and the sternum (breastbone). Irregular bones: Irregular bones are irregular in size and shape and are usually quite compact.
Explanation:
Answer:
Girls have menstrual cycles because girls have changes of hormones in their body. The hormones make the lining of the uterus build up. This gets the uterus ready for an egg which when the egg is released it causes a period also known as a menstrual cycle which happens normally every month for at least 3-7 days.
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