The intensity of a physical activity will be reflected with the speed at which the activity is carried out or the magnitude of the effort required to perform an exercise.
A moderate physical activity requires moderate effort, which noticeably accelerates the heart rate, but you can usually carry on a conversation. For example walking. Instead vigorous physical activity is going to require a great deal of effort and causes rapid breathing and a substantial increase in heart rate. For example surfing, playing tennis, horseback riding, biking, dancing and swimming.
People with type O- blood are called universal donors because their donated red blood cells have no A, B or Rh antigens and can therefore be safely given to people of any blood group.
