What is the overall cell potential for this redox reaction? ca2+ + 2li = ca + 2li+ ca2+ + 2e- = ca -2.87 v li = li+ + e- -3.05 v

The redox reaction is

Here

Calcium undergoes reduction, and acts as cathode

Lithium undergoes oxidation and acts as anode

The reduction potential of calcium is -2.87 V

The reduction potential of lithium is - -3.05 V

We know that

Ecell = Ecathode - Eanode

Ecell = -2.87 - (-3.05)  = 0.18 V

organisms are more likely to be more preserved in mud than sand because mud is moist and wet, while sand is very dry.