The role of haemoglobin is to

An ice ball melts at a rate proportional to the amount of ice present at that instant. Half the quantity of ice melts in $20 \text{ minutes}$. Let $x_0$ be the initial quantity of ice. If after $40 \text{ minutes}$ the amount of ice left is $k x_0$,then the value of $k$ is:

The synthesis of $ATP$ in photosynthesis and respiration is essentially an oxidation-reduction process involving the removal of energy from:

At a certain instant, a stationary transverse wave is found to have maximum kinetic energy. The appearance of the string at that instant is:

The simplest formula of a compound containing $50\%$ of element $X$ (atomic mass $10$) and $50\%$ of element $Y$ (atomic mass $20$) is

The force acting on a body moving along the $x-$axis varies with the position of the particle as shown in the figure. The body is in stable equilibrium at