Explanation

The combination formula is:

nCr = n! / (r!(n-r)!)

Given that nC12 = nC6, we can equate the two expressions:

n! / (12!(n-12)!) = n! / (6!(n-6)!)

Simplifying the equation, we get:

12!(n-12)! = 6!(n-6)!

Since 12! = 12 × 11 × 10 × 9 × 8 × 7 × 6!, we can cancel out the 6! terms:

12 × 11 × 10 × 9 × 8 × 7 = (n-6)(n-7)(n-8)(n-9)(n-10)(n-11)

This equation is true when n = 18.

Therefore, the correct answer is 18.

Explanation

• Protein synthesis is a function of cells, specifically ribosomes, which are found in the cytoplasm of cells.
• Bones do not play a direct role in protein synthesis.

Explanation

• The given equation (x + 2)^2 = x^2 + 4x + 4 is an identity because it is true for all values of x.
• An identity is an equation that is always true, and this equation is simply the result of expanding the left-hand side using the binomial theorem.

Explanation

• This is the standard SQL syntax to drop a column from a table.
• The ALTER TABLE statement is used to modify the structure of a table, and the DROP COLUMN clause is used to delete a column.
• An example: ALTER TABLE MyTable DROP COLUMN MyColumn;

Explanation

• A microcontroller at least consists of a processor as its CPU with RAM, ROM, I/O ports and timers.
• It may contain some additional peripherals like ADC, PWM, etc.

Explanation

The db_accessadmin role manages security, but handles access to the database, as the name implies.

Explanation

• About 75% of elements in the periodic table are metals.
• The periodic table is divided into metals, nonmetals, and metalloids. 
• The classification of elements as metals, nonmetals, or metalloids is based on their physical and chemical properties.

Explanation

• A buffer solution is a mixture of a weak acid and its conjugate base, or a weak base and its conjugate acid, that resists changes in pH when an acid or base is added to it.
• This is because the acid and its conjugate base (or the base and its conjugate acid) react with the added acid or base to maintain the equilibrium, keeping the pH constant.

Explanation

• Lone pairs are pairs of outer shell electrons that are not used in bonding. They are also known as non-bonding pairs or unshared pairs.
• These electrons are typically found in the outermost energy level (valence shell) of an atom and are not involved in forming chemical bonds with other atoms.

Explanation

• A stone whirling in a horizontal circle on the end of a string is a classic example of a conical pendulum, a type of physical system that demonstrates principles of circular motion, centrifugal force, and angular momentum.
• The string traces out a cone-shaped path, hence the name "conical pendulum".
• This is different from a simple pendulum, which swings back and forth in a vertical plane.