Care plan "aeb" same as objective/subjective ??

• Problem - this is the nursing diagnosis. A nursing diagnosis is actually a label. To be clear as to what the diagnosis means, read its definition in a nursing diagnosis reference or a care plan book that contains this information. The appendix of Taber's Cyclopedic Medical Dictionary has this information.
• Etiology- also called the related factor by NANDA. This is what is causing the problem. It is the reason the problem exists and reasons can be many and varied. Ask yourself "Why did this happen?" or "How did this problem come about?" "What caused this to become a problem in the first place?" And dig deep. Consider the medical diagnosis, the medical treatments that were ordered and the patient's ability to perform their ADLS. Pathophysiologies need to be examined to find these etiologies if they are of a physiologic origin. It is considered unprofessional to list a medical diagnosis, so a medical condition must be stated in generic physiological terms. You can sneak a medical diagnosis in by listing a physiological cause and then stating "secondary to (the medical disease)" if your instructors will allow this.
• Symptoms- also called defining characteristics by NANDA, these are the abnormal data items that are discovered during the patient assessment. They can also be the same signs and symptoms of the medical disease the patient has, the patient's responses to their disease, and problems accomplishing their ADLs. They are evidence that prove the existence of the nursing problem. If you are unsure that a symptom belongs with a nursing problem, refer to a nursing diagnosis reference. These symptoms will be the focus of your nursing interventions and goals.

Yes. The signs and symptoms, or abnormal assessment data that you link to a particular nursing problem (nursing diagnosis) are proof that the problem exists.

Why does it only have to be one or two? I'd list all the signs and symptoms of the problem the patient has. You know why? Because your care plan will probably involve treating each of them. If you had to pick only one or two, use Maslow and pick the ones that if they go untreated are going to cause the worst damage to the patient.