Why do we think that some cell signaling molecules have a long evolutionary history?

Cell signaling involves the relationship between a cell and its receptor which gets the hormones and other agents which controls the activity of the cell.

Explanation:

It can be classified as mechanical or biochemical depending upon the kind of signal. Mechanical signals are the forces produced by the cell or exerted by the cell. Biochemical signals are derived by the biomolecules like proteins, ions, gases, and lipids. These biomolecules have an evolutionary history as they are developed during the primitive atmosphere of earth by the inorganic molecules of carbon dioxide, methane, and water present in the primitive earth's atmosphere. These molecules are basis of development of life as they were responsible for generation of biomolecules like proteins, and lipids necessary for sustaining life on earth.

rocks and weathering-matching

explanation:

on disadvantage of hydroelectric power is the cost. another disadvantage of using hydroelectric power is finding a water source powerful enough to harvest hydroelectric power.