I believe it is a araebacteria
Be more specific please on this question
Survival of the fittest is talking about when you have traits that will help you, you are more likely to live rather than not having those traits. For example, a bird that swims a lot has webbed feet so it has a better chance of surviving then a bird who does not have webbed feet
The area is called the anterior fontanel and closes anytime between 9 and 18 months of age.