The jawless vertebrate is

The area (in sq unit) of the region bounded by the curves $2x = y^2 - 1$ and $x = 0$ is

Match the following columns:

Column-$I$	Column-$II$
$a$. Bicuspid valve	$p$. Brain
$b$. Nephron	$q$. Liver
$c$. Alveoli	$r$. Heart
$d$. Cerebrum	$s$. Kidney
	$t$. Lungs

Chemical $A$ is used for water softening to remove temporary hardness. $A$ reacts with sodium carbonate to generate caustic soda. When $CO_2$ is bubbled through $A$,it turns cloudy,what is $A$?

Venus appears brighter than other stars because

The electrochemical equivalent of a metal is $x \ g \ C^{-1}$. The equivalent weight of the metal is: