The water from natural resources contain minerals that change the ph of water.
Sounds like Your cardiovascular system, the closed tubes must be your blood vessels, siencey term: your Angio, which means blood vesels
Earthquakes with magnitudes between 1.0 and 2.9 on the richer scale are low, and usually not felt.
I believe this is the cell wall
Nutrient cycle is the biogeochemical cycle that<span> includes exoskeleton and shells of marine organisms as a reservoir. This cycle involves the exchange of organic and inorganic matter back to the living production of matter. The decomposition of exoskeleton and shells of marine organisms will give nutrients which will be used in this cycle.</span>