What is common among silverfish,scorpion,crab,and honeybee?

$A$ and $B$ are two substances undergoing radioactive decay in a container. The half-life of $A$ is $15 \ min$ and that of $B$ is $5 \ min$. If the initial concentration of $B$ is $4$ times that of $A$ and they both start decaying at the same time,how much time will it take for the concentration of both of them to be same? $.......... \ min$

The cut flowers and vegetables can be kept fresh for a long period by this plant hormone.

$A$ convex mirror of focal length $f$ forms an image which is $1/n$ times the object. The distance of the object from the mirror is

When zeolite is treated with hard water,the sodium ions are exchanged with

$\sin ^{-1}\left(\sin \frac{7 \pi}{6}\right) = $