Which of the following is an extinct human species?

The coefficient of $x^{10}$ in the expansion of $(2+3x)e^{-x}$ is

Bromine is commercially prepared from sea water by displacement reaction:
$Cl_2 + 2Br^{-}_{(aq)} \to 2Cl^{-}_{(aq)} + Br_2$
$Br_2$ gas thus formed is dissolved into a solution of $Na_2CO_3$ and then pure $Br_2$ is obtained by treatment of the solution with:

$A$ bag contains $5$ black balls,$4$ white balls and $3$ red balls. If a ball is selected at random,the probability that it is a black or a red ball is:

$2\,g$ of steam condenses when passed through $40\,g$ of water initially at $25\,^{\circ}C$. The condensation of steam raises the temperature of water to $54.3\,^{\circ}C$. What is the latent heat of steam in $cal/g$?

$A$ bryophyte,which harbours a nitrogen-fixing blue-green alga in its thallus,is