Identify from the following,a plant tissue in which lignin does not occur in the cell walls?

In which of the following is lead sulfate $(PbSO_4)$ soluble?

$\sqrt{3} \operatorname{cosec} 20^{\circ} - \sec 20^{\circ}$ is equal to

Which of the following is the most basic oxide?

$A$ pair of perpendicular lines passes through the origin and also through the points of intersection of the curve $x^2+y^2=4$ with $x+y=a$,where $a>0$. Then $a$ is equal to

Identify the major product of the following reaction: