In which of the following is the gametophytic phase reduced,short-lived,and limited to the formation of gametes?

Wilting occurs when

$A$ lead bullet at $27\,^oC$ just melts when stopped by an obstacle. Assuming that $25\%$ of the heat produced is absorbed by the obstacle,the velocity of the bullet at the time of striking is ........ $m/s$. (Melting point of lead $= 327\,^oC$,specific heat of lead $= 0.03\,cal/g\,^oC$,latent heat of fusion of lead $= 6\,cal/g$,and $J = 4.2\,J/cal$)

The intensity of the electric field required to keep a water drop of radius $10^{-5} \, cm$ just suspended in air when charged with one electron is approximately:

If the area of the triangle formed by the pair of lines $8x^2 - 6xy + y^2 = 0$ and the line $2x + 3y = a$ is $7$,then $a$ is equal to

Which one of the following orders presents the correct sequence of the increasing basic nature of the given oxides?