When two sea caves on opposite sides of a headland are eroded and unite a sea arch forms.
Sea arch is a natural opening and a type of erosional landform that forms due to different rates of erosion, usually as a result of different resistance of bedrock. Sea arch is made up of a soft rock that eroded as waves hit land which creates caves in the rock. Two caves may become jointed over some time to form a tunnel and eventually, a sea arch.
The carbon cycle is nature's way of reusing carbon atoms, which travel from the atmosphere into organisms in the Earth and then back into the atmosphere over and over again. Most carbon is stored in rocks and sediments, while the rest is stored in the ocean, atmosphere, and living organisms.
Selective permeable means it selects what goes out and comes into the cell. If the cell membrane wasnt selective then things could enter the cell and destroy it.
