Author name: Umar Draz

Why? A picosecond is one trillionth of a second (10⁻¹²). It is used in physics and electronics to measure extremely fast events such as molecular vibrations or high-speed signal transmission.

Why? The plasma membrane forms the outer boundary of animal cells, separating internal contents from the external environment. In plants, the cell wall is outermost, so the plasma membrane is not the outer covering.

Why? In a vacuum, electromagnetic waves always travel at the speed of light (≈ 3×10⁸ m/s), regardless of their frequency or intensity.

ANSI

Why? The COUNTA() function counts all non-empty cells, including those with numbers, text, logical values, or formulas. It does not count only numeric cells (that is COUNT()).

Why? A20:A31 refers to a continuous range of cells starting from cell A20 down to A31 in column A.

Why? A pixel is the smallest individual element of a digital image or display. Each pixel carries color and brightness information to form a complete picture.

Why? Let the original price be x. After 20% discount, selling price = 80% of x. So, 0.8x = 596 → x = 596 ÷ 0.8 = 745.

Why? “Prolong” means to lengthen or extend the duration of something, so the closest synonym is “Extend.”

Why? The correct idiom is “laugh in one’s sleeve,” meaning to hide one’s amusement secretly.