O M G i just did that one on Plato
well anyway i think the answer was the the skin because any thing that invades the body is a threat to the immune system.
Answer:
not sure if this helps but. Concept development is a set of activities that are carried out early in the systems engineering life cycle to collect and prioritize operational needs and challenges, develop alternative concepts to meet the needs, and select a preferred one as the basis for subsequent system or capability development
Answer: Poor personal hygiene habits, however, can lead to some minor side effects, like body odor and greasy skin. They can also lead to more troublesome or even serious issues. For example, if you don't wash your hands frequently, you can easily transfer germs and bacteria to your mouth or eyes.
The brain releases endorphins while exercising, the release of these endorphins tend to make people happy.
An example would be good things, like a wedding or date or anything positive.
