Speed is a scalar quantity but has no direction whereas, velocity is a magnitude which includes direction. A vector has magnitude and direction.
The salt water consists mostly of the following substances: dissolved salts (predominantly sodium (Na+ ) and chloride (Cl− ) ions.<span>The other most </span>abundant<span> ions of </span>seawater<span> are</span> sulfate (SO24−), magnesium (Mg<span>2+</span>), calcium (Ca<span>2+</span>), and potassium (K+<span>).</span>
Species. It is the last taxonomic level
It would mean that the organisms rely on each other for survival.
Hope this helps (:
D because both a & b are correct