What do herbicides primarily interfere with?

The ratio of the areas bounded by the curves $y = \cos x$ and $y = \cos 2x$ between $x = 0,$ $x = \pi /3$ and the $x$-axis is:

If $g$ is the acceleration due to gravity on the earth's surface,the gain in the potential energy of an object of mass $m$ raised from the surface of the earth to a height equal to the radius $R$ of the earth,is

$A$ ray of light passes through an equilateral prism $(\mu = 1.5)$ such that the angle of incidence is equal to the angle of emergence,and the latter is equal to $3/4$ of the prism angle. The angle of deviation is....$^o$

Read the following five statements ($a$ to $e$) and select the option with all correct statements:
$(a)$ Mosses and Lichens are the first organisms to colonise a bare rock.
$(b)$ $Selaginella$ is a homosporous pteridophyte.
$(c)$ Coralloid roots in $Cycas$ have $VAM$ mycorrhizae.
$(d)$ Main plant body in bryophytes is gametophytic,whereas in pteridophytes it is sporophytic.
$(e)$ In gymnosperms,male and female gametophytes are present within sporangia located on sporophyte.

The three boxes in this diagram represent the three major biosynthetic pathways in aerobic respiration. Arrows represent net reactants or products. Arrows numbered $4, 8, 12$ can all be