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 viewed on an atomic and molecular scale as shown in this article. The estimated gross molecular contents of a typical 20-micrometre human cell is as follows: Body composition can also be expressed in terms of various types of material, such as: There are many species of bacteria and other microorganisms that live on or inside the healthy human body. In fact, 90% of the cells in (or on) a human body are microbes, by number (much less by mass or volume). Some of these symbionts are necessary for our health. Those that neither help nor harm humans are called commensal