Who discovered $TMV$ (Tobacco Mosaic Virus)?

In angiosperms,the functional megaspore develops into:

Which of the following is the correct order for basic strength?

Calcium carbonate reacts with aqueous $HCl$ to give $CaCl_2$ and $CO_2$ according to the reaction given below: $CaCO_{3(s)} + 2HCl_{(aq)} \to CaCl_{2(aq)} + CO_{2(g)} + H_2O_{(l)}$
What mass of $CaCl_2$ will be formed when $250 \ mL$ of $0.76 \ M$ $HCl$ reacts with $1000 \ g$ of $CaCO_3$? Name the limiting reagent. Calculate the number of moles of $CaCl_2$ formed in the reaction.

Which of the following is the strongest conjugate base?

The number of tetrahedral voids present in $0.5 \text{ mole}$ of an $hcp$ crystal structure is: