$Na_2S_2O_3$ reacts with moist $Cl_2$ to form $Na_2SO_4$,$HCl$ and $X$. Which one of the following is $X$?

The major product of the following reaction is

If $s$ and $p$ are respectively the sum and the product of the slopes of the lines $3x^2 - 2xy - 15y^2 = 0$,then $s:p$ is equal to

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.

Temperate evergreen forests are found in

Which of the following wiring diagrams could be used to experimentally determine $R$ using Ohm's law? Assume an ideal voltmeter and an ideal ammeter.