mental illness in which an individual expresses psychotic, negative and cognitive symptoms that affect their thoughts, emotions, and actions. Often with an onset from teenage years to thirties.

If you could explain more about the question, I can help!!

Explanation:

I'm assuming that you want me to describe a certain mental illness?

An example of a mental illness is Obsessive Compulsive Disorder, also known as OCD. OCD is where you obsess over certain thoughts and objects, and cannot control it. It is commonly concieved through compulsions, like rewriting a sentence numerous times to make it 'perfect' to the person with OCD. In most cases of OCD, the person suffering from the illness cannot help it. It affects their emotions through others becoming annoyed around them due to their obsessions or compulsions. If the person with OCD cannot express their compulsions, it'll be worse later on, as if something exploded. An example of a compulsion is to tap the bed 3 times. To control it, the person may count 3 times in their head instead. A common misconception of OCD is that people with the illness are constantly washing their hands or cleaning, which can happen, but usually doesn't.

Sorry it's a bit messy, but I hope this helps!!

answer(b) keep oxygenated and deoxygenated blood separate;