The principle of immunization or vaccination is based on the property of ...........

Ephemerals are xerophytes that are:

Which of the following is $NOT$ included in $In-situ$ conservation?

Which of the following is not true for a eukaryotic cell?

The maximum area of a right-angled triangle with hypotenuse $h$ is

$A$ and $B$ are two radioactive substances whose half-lives are $1$ and $2$ years respectively. Initially, $10 \, g$ of $A$ and $1 \, g$ of $B$ are taken. The time (approximate) after which they will have the same quantity remaining is ........... $years$.