Cardiac muscle fibers differ from skeletal muscle fibers in that they are -

Which of the following compounds is not chiral?

$A$ stone of mass $m$ is tied to a string and is moved in a vertical circle of radius $r$ making $n$ revolutions per minute. The total tension in the string when the stone is at its lowest point is

Read the following five statements $(1-5)$ carefully and answer the question that follows.
$(1)$ In $Equisetum$,the female gametophyte is retained on the parent sporophyte.
$(2)$ In $Ginkgo$,the male gametophyte is not independent.
$(3)$ The sporophyte of $Polytrichum$ is more developed than that of $Riccia$.
$(4)$ Sexual reproduction in $Volvox$ is isogamous.
$(5)$ Spores of slime molds lack a cell wall.
How many of the above statements are correct?

Which of the following reactants can be reduced by $SO_2$?
$I$. $O_3 \to$ product
$II$. $Cr_2O_7^{2-} \xrightarrow{H^{+}} $ product
$III$. $MnO_4^- \xrightarrow{H^{+}} $ product
$IV$. $H_2S \longrightarrow $ product

Which one of the following metallic hydroxides does not dissolve in sodium hydroxide solution?