What is the use of Guayule ($Parthenium$ $argentatum$)?

The value of $\lambda$ such that $\lambda x^2-10 x y+12 y^2+5 x-16 y-3=0$ represents a pair of straight lines is:

$A$ particle is executing simple harmonic motion with an amplitude $A$ and time period $T$. The displacement of the particle after $2T$ time from its initial position is

If the $x$-coordinate of a point $P$ on the line joining the points $Q(2, 2, 1)$ and $R(5, 1, -2)$ is $4$,then the $z$-coordinate of $P$ is

Assertion $(A)$: $-NH_2$ group of aniline is ortho,para directing in electrophilic substitutions.
Reason $(R)$: $-NH_2$ group stabilises the arenium ion formed by the ortho,para attack of the electrophile.
The correct answer is

Which of the following plant groups produces seeds but is non-flowering?