Which of the following exhibits a haplontic life cycle?

Which one of the following reactions is an example of heterogeneous catalysis?

At what speed should a source of sound move so that a stationary observer finds the apparent frequency equal to half of the original frequency?

One of the parents of a cross has a mutation in its mitochondria. In that cross,that parent is taken as a male. During segregation of $F_{2}$-progenies,that mutation is found in:

If $x$ is a solution of the equation $\sqrt{2x+1} - \sqrt{2x-1} = 1$ where $x \geq \frac{1}{2}$,then $\sqrt{4x^2-1}$ is equal to

Two particles $P$ and $Q$ start from the origin and execute Simple Harmonic Motion along the $X$-axis with the same amplitude but with periods $3 \ s$ and $6 \ s$ respectively. The ratio of the velocities of $P$ and $Q$ when they meet is