<span>The thymus.The thymus plays an important role in the development of T-lymphocytes which is an important type of white blood cell. It reaches maximum development at puberty and then the thymus begins to get atrophied (the shrinking of the thymus with age) and then the thymic stroma is replaced by fat tissue. Loss of thymic function is thought to contribute to weaker immune system of the elderly, increasing instances of diseases such as cancers and other infections.</span>
Not sure if you still need the answer but its number Three, they are the decomposers in many ecosystems
Splash large amounts of water to dilute the spill. Stand back and advise the teacher of the spill. Immediately ask to go to the restroom.
I think this would be the environment. That's my guess