The decreasing order of nucleophilicity among the following nucleophiles is:
$(I)$ $CH_3-COO^-$
$(II)$ $CH_3-O^-$
$(III)$ $CH_3-CH_2^-$
$(IV)$ $CH_3-SO_3^-$

Breeding of crops with high levels of minerals,vitamins,and proteins is called:

$A$ ball of mass $2\;kg$ and another of mass $4\;kg$ are dropped together from a $60\;ft$ tall building. After a fall of $30\;ft$ each towards the Earth,their respective kinetic energies will be in the ratio of?

The angle between the lines whose direction cosines satisfy the equations $l+m+n=0$ and $l^2+m^2-n^2=0$ is

Two towers $A$ and $B$,each of height $20 \ m$,are situated a distance $200 \ m$ apart. $A$ body is thrown horizontally from the top of tower $A$ with a velocity $20 \ ms^{-1}$ towards tower $B$ and hits the ground at point $P$. Another body is thrown horizontally from the top of tower $B$ with a velocity $30 \ ms^{-1}$ towards tower $A$ and hits the ground at point $Q$. If a car starting from rest from point $P$ reaches point $Q$ in $10 \ s$,the acceleration of the car is . . . . . . . (Acceleration due to gravity $g = 10 \ ms^{-2}$) (in $ms^{-2}$)

$1+\frac{1}{3 \cdot 2^2}+\frac{1}{5 \cdot 2^4}+\frac{1}{7 \cdot 2^6}+\ldots$ is equal to