$x$ grams of calcium carbonate was completely burnt in air. The weight of the solid residue formed is $28 \text{ g}$. What is the value of $x$ (in grams)?

The following are some statements related to $VA$ group hydrides:
$I$. Reducing property increases from $NH_3$ to $BiH_3$.
$II$. Tendency to donate lone pair decreases from $NH_3$ to $BiH_3$.
$III$. Thermal stability of hydrides decreases from $NH_3$ to $BiH_3$.
$IV$. Bond angle of hydrides decreases from $NH_3$ to $BiH_3$.
The correct statements are:

If the mean and variance of a binomial variable $X$ are $2$ and $1$ respectively,then $P(X \geq 1)$ is equal to

Modern cereal $Triticale$ is developed by crossing between

An animal phylum having radially symmetrical adults but bilateral symmetrical larvae is

Bulk of carbon dioxide $(CO_2)$ released from body tissues into the blood is present as