The total number of nitrogenous bases in the human genome is estimated to be about

Identify the correct order in which the covalent radius of the following elements increases: $(I)$ $Ti$,$(II)$ $Ca$,$(III)$ $Sc$.

The simplest and most primitive embryophytes are ......

$A$ steel meter scale is to be ruled so that millimeter intervals are accurate within about $5 \times 10^{-5} \ m$ at a certain temperature. The maximum temperature variation allowable during the ruling is (Coefficient of linear expansion of steel $= 10 \times 10^{-6} \ K^{-1}$) (in $^{\circ} C$)

An observer moves towards a stationary source of sound with a speed $1/5^{th}$ of the speed of sound. The wavelength and frequency of the source emitted are $\lambda$ and $f$ respectively. The apparent frequency and wavelength recorded by the observer are respectively: