Patella pellucida "Fucus serratus" on the lower shore, down to about 30 m. The larvae of this limpet species settle and metamorphose on the algal frond. Here it feeds on its host’s tissue using its radula, leaving small depressions in the frond. As the limpets grow larger, they move down the stipe of the seaweed towards the holdfast, where they establish themselves by excavating a depression. This can weaken the holdfast, eventually resulting in the seaweed being dislodged by storms. The seaweed is often washed ashore, with the blue-rayed limpets still in place. Patella pellucida Patella pellucida, common name the blue-rayed limpet,
Composition of the human body mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium. All 11 are necessary for life. The remaining elements are trace elements, of which more than a dozen are thought on the basis of good evidence to be necessary for life. All of the mass of the trace elements put together (less than 10 grams for a human body) do not add up to the body mass of magnesium, the least common of the 11 non-trace elements.