The charge on colloidal particles is due to

Into how many subclasses is the class $Dicotyledonae$ divided?

$A$ uniform meter scale is balanced at the $30 \ cm$ mark on a knife edge,when weights of $60 \ N$ and $10 \ N$ are suspended at the $10 \ cm$ and $80 \ cm$ marks,respectively. The mass of the meter scale is: (in $kg$)

Flame cells are the excretory organs of

Which of the following characters are related with Poaceae family?
$(a)$ Basal placentation
$(b)$ Feathery stigma
$(c)$ Cypsela fruit
$(d)$ Pentamerous flower

Which property among the following is the same for both hydrogen and deuterium molecules?