During which phase of meiosis does crossing over occur?

The power dissipated in the circuit shown in the figure is $30 \, W$. The value of $R$ is ............. $\Omega$.

Olfactoreceptors are:

The $P-V$ diagram of a diatomic gas is a straight line passing through the origin. The molar heat capacity of the gas in the process will be:

If $A$ and $B$ are events of a random experiment such that $P(A \cup B) = \frac{4}{5}$,$P(\bar{A} \cup \bar{B}) = \frac{7}{10}$ and $P(B) = \frac{2}{5}$,then $P(A)$ equals

$A$ plane $x$ passes through the point $(1, 1, 1)$. If $b, c, a$ are the direction ratios of a normal to the plane, where $a, b, c$ $(a < b < c)$ are the factors of $2001$, then the equation of the plane is