Diatoms are one of the most important and abundant components of marine phytoplankton with two valves (frustules) composed mainly of silica (SiO2). Average size is 10-100µm
Inhabit all aquatic environments. They occur in the body of the water as plankton or on the bottom where they may be attached to plants or rocks or sand particles or maybe free-living and able to move between particles of the substratum. In the open ocean, they live only in the upper 200 m of the surface water.
Diatoms produce an estimated 20% to 25% photosynthesis on the planet
.
Hence, diatoms are correct answer this is because the primary producer it must be resistant to physical damage from wave action
