What are plasmodesmata?

Electric charges of $+10\,\mu C$,$+5\,\mu C$,$-3\,\mu C$,and $+8\,\mu C$ are placed at the corners of a square of side $\sqrt{2}\,m$. The potential at the centre of the square is:

Among the electrolytes $Na_2SO_4$,$CaCl_2$,$Al_2(SO_4)_3$ and $NH_4Cl$,the most effective coagulating agent for $Sb_2S_3$ sol is

The output of the given logic circuit is

In contrast to annelids,the Platyhelminthes show:

Which of the following crops were introduced into India from the New World?