Answer: The geologic time scale is the “calendar” for events in Earth history. It subdivides all time into named units of abstract time called—in descending order of duration—eons, eras, periods, epochs, and ages.
Explanation: I learned about it the other day
Covalent bonding is when electrons are shared between atoms.
<span>The answer is B. Convection occurs when hot/warm
water rise to the top and the cold water goes to the bottom in a vessel. This is
because hot/warm water is less dense than cold water. Additionally, convection
currents are well perceptible in air and water and fluid substances that are
poor conductors of heat</span>
We take activities of Solids and liquids equal 1. The reason is there concentrations not at all change amount of reactant at equilibrium in the reaction. Hence we don't consider concentrations of pure solids and liquids while writing equilibrium constant.
So for above reaction, equilibrium constant (K) = [Sn^2 +] ^3 x 1 / [Fe^3+]^2 x 1. Ping me if you have any doubts.