The world's second nuclear explosion was achieved with uranium-235. This isotope is unstable and fissions when struck by a neutron. It is, however, found in natural uranium at a concentration of only 0.7 percent. To be useful in nuclear weapons, the concentration must be increased.
Introduction. Influenza, or flu, is a caused by a virus infecting the respiratory system, meaning your nose, throat, bronchial tubes, and lungs. Flu symptoms are usually more severe than those of the common cold and are more likely to affect other parts of your body.
Influenza B is a type of flu virus that can cause respiratory, fever and stomach symptoms. Influenza or the flu refers to a respiratory infection that can be caused by a variety of types of viruses. The virus will move through the air and become inhaled through the mouth or nose.