The nucleophilic addition reaction depicted below involves a prochiral ketone carbon atom reacting with a nucleophilic hydride ion source (LiAlH4 or NaBH4) and, subsequently, a proton source (e. g., H2O or dilute aq. HCl). Consequently, the reaction produces a racemic mixture of an alcohol. Finish drawing the structures of the products resulting from nucleophilic attack upon the front and back faces of the carbonyl group, being careful to specify the stereochemistry via wedge-and-dash bonds.

we are given the 3-methyl2 butanone and upon the reduction with LiAIH4 there is formed alcohol, there are two possible side attack,

therefore, whenever the front side attacks then the -CH3 moves back  the plain and the H will be above the plane. More so, when  attack from the back side the H moves below the plane and -CH3 moves above the plane. -OH is evident in the plane. see the attachment below to view the structure.

Explanation:

beta decay is the answer

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.