The correct sequence of increasing covalent character is represented by

$A$ body is sliding down a rough inclined plane. The coefficient of friction between the body and the plane is $0.5$. The ratio of the net force required for the body to slide down and the normal reaction on the body is $1:2$. Then the angle of the inclined plane is: (in $^{\circ}$)

In which of the following,ortho/para substitution by an electrophile is very facile?

Modern farmers have been able to increase rice production by $50\%$ using which of the following?

Which of the following is less general in characters as compared to genus?

The number of circles that touch all the three lines $x+y-1=0$,$x-y-1=0$,and $y+1=0$ is