The immune system recognizes and destroys substances that contain antigens. Your body's cells have proteins that are antigens. These include a group of antigens called HLA antigens. Your immune system learns to see these antigens as normal and usually does not react against them.
Mother's Day 2016. Need to know the exact date of Mothers Day this year? Here's a chart that shows what day Mother's Day is celebrated from 2014 - 2021. In the US, Mother's Day is celebrated on the second Sunday in May. In the UK, mothers are honored the fourth Sunday of Lent. Check out our fun Mother's Day Games and Activities for teachers!
Mother's Day isn't a new holiday. The earliest Mother's Day celebrations can be traced back to the spring celebrations of ancient Greece in honor of Rhea, the mother of the gods. People would make offerings of honey-cakes, fine drinks, and flowers at dawn.