A vaccine is meant to train your immune system to recognize a virus so it can fight off that virus if you ever come in contact with it.
When we sleep we go through different types of sleep stages. You have slow-wave sleep, which is like your deep sleep, and then there’s dream sleep, which is called REM sleep.
This question brings up all kinds of interesting issues about who we are as humans and how we compare to other animals.
When the eye color, or iris color, is different between the two eyes, the condition is called iris heterochromia.
This is a question scientists are still trying to figure out. We know that it has to do with the specific genetic makeup, and everyone has slight differences in metabolism.