Biologic evolution

There is my only one experiment tool.
The reason for I is that it is a scientist and I am not a teacher.

The tool that I am using is S28E made by the ATAGO company.
The function is to be able to measure the salt 0~28 percent.
The method of the display is g/100g.

The density of salinity of seawater is measured.
The measurement changes by rain and the snow.
The measurement day is fine weather. Seawater is 1.8g/100g.
The seawater that Asari's shellfish has is measured by using S28E.
Seawater in Asari's shell is 2.1g/100g.

Result of experiment.
The salinity of nourishment (seawater) in Asari's husk will be more than that of seawater.
Asari : though it understands when the photograph is seen.
It is understood not to be open of the shellfish in the sea.

Perhaps, it can be guessed that the density of salinity in the shellfish is prevented from falling.