$AA^T = 9I$ means each row has magnitude 3 and rows are mutually orthogonal.

Row 1: $1^2+2^2+2^2=9$ ✓

Row 2: $4+1+4=9$ ✓

Row 3 magnitude: $a^2+4+b^2=9 \Rightarrow a^2+b^2=5$ ...(i)

Row 1 · Row 3: $a+4+2b=0 \Rightarrow a+2b=-4$ ...(ii)

Row 2 · Row 3: $2a+2-2b=0 \Rightarrow a-b=-1$ ...(iii)

From (ii) and (iii): subtracting gives $3b=-3 \Rightarrow b=-1$, then $a=-2$. Check (i): $4+1=5$ ✓

$(a,b) = \mathbf{(-2,-1)}$

The time period is $T = 2\pi\sqrt{L/g}$, meaning $L \propto T^2$ [cite: 437].

• Initial length $L = kT^2$ and new length $L' = kT_M^2$
• Extension $\Delta L = L' - L = k(T_M^2 - T^2)$
• Strain $\frac{\Delta L}{L} = \frac{T_M^2 - T^2}{T^2} = (\frac{T_M}{T})^2 - 1$
• From $Y = \frac{\text{Stress}}{\text{Strain}} = \frac{Mg/A}{\Delta L/L}$, we get $\frac{1}{Y} = [(\frac{T_M}{T})^2 - 1]\frac{A}{Mg}$[cite: 437, 440].

Creativity is specifically defined as the thinking process involved in producing ideas or concepts that are new, original, and useful. While innovation involves implementing creative ideas, and intelligence involves applying knowledge, creativity is the term for the generative cognitive process itself.

Correct Answer: A — Creativity.

Oxidative phosphorylation occurs in the inner mitochondrial membrane (or bacterial plasma membrane) via the electron transport chain and ATP synthase. It couples chemiosmosis with ATP synthesis.