The groind tissue in roots

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?

The small molecule cyclic amp (camp) takes about 0.2 second to diffuse 10 μm, on average, in a cell. suppose that camp is produced near the plasma membrane on one end of the cell; how long will it take for this camp to diffuse through the cytosol and reach the opposite end of a very large cell, on average? assume that the cell is 200 μm in diameter.

What factors contribute to the effect an environmental toxin has on the human body?