The structure of $Cl_2O_7$ is ......

Which of the following mixtures is known as fusion mixture?

$A$ - Events after the formation of zygote are called post-fertilization events.
$R$ - In viviparous animals,a young one develops outside the mother's body.

Choose the correct option from the following:
$I$. Dehydration and dormancy of mature seed are crucial for seed storage.
$II$. Seed of $Lupinus \; arcticus$ is the oldest one which germinated after $2,000 \; years$.
$III$. Orchid seed is one of the largest seeds in the plant kingdom.
$IV$. Seeds of parasitic plants $Orobanche$ and $Striga$ are tiny seeds.

$A$ motor of power $P_0$ is used to deliver water at a certain rate through a given horizontal pipe. To increase the rate of flow of water through the same pipe $n$ times,the power of the motor is increased to $P_1$. The ratio of $P_1$ to $P_0$ is

With increasing principal quantum number,the energy difference between adjacent energy levels in $H$ atom