Which property among the following is the same for both hydrogen and deuterium molecules?

The packing efficiency of the two-dimensional square unit cell shown below is ........... $\%$

If $(a+\sqrt{2} b \cos x)(a-\sqrt{2} b \cos y)=a^{2}-b^{2}$ where $a>b>0,$ then $\frac{dx}{dy}$ at $\left(\frac{\pi}{4}, \frac{\pi}{4}\right)$ is

There are $9$ balls to be placed in $9$ boxes. If $5$ of the balls cannot fit into $3$ specific small boxes,find the number of ways of arranging one ball in each of the boxes.

Which of the following anthropogenic actions leads to evolution?

Two electrons occupying the same orbital are distinguished by