I believe the closest answer would be viruses (Though viruses aren't actually living) viruses constantly change, so much that scientists don't know how many types of viruses there are in the world. For example, chicken pox is caused by a virus, however, the virus changes and becomes dormant until a stimulus of any sort activates it again and this is where you can get shingles. The reason why the immune system couldn't recognize the chicken pox virus is that it had changed and became dormant, and when the virus woke up again, it introduced a new illness, shingles.
I think this answer is either A or D
Id say one meaningful use would be the actually caring and holding responsibility for a patient. Being able to be a strong support not only emotionally but informationally. you are able to inform them on matters that regard their health.
Answer:
strength of positive expectancies about alcohol
older sibling's relationship style
You can write up a petition or raise money for the school. If you raise enough money then it can put the P.E class back on track. Without Physical Education your classmates will gain weight and not know how to eat and live healthily.