Which of the following pairs of molecules is isostructural?

What is the molecular geometry of $H_3O^{+}$?

What is the correct order of bond angles in $H_2O, NH_3, CH_4, CO_2$?

The isostructural molecules among $CO_2, SiO_2, SO_2, TeO_2, [NO_2]^{+}$ are

The bond angles in methane $(I)$,ammonia $(II)$,and trimethylamine $(III)$ increase in the order:

The number of species from the following carrying a single lone pair on the central atom Xenon is $.....$: $XeF_5^{+}, XeO_3, XeO_2F_2, XeF_5^{-}, XeO_3F_2, XeOF_4, XeF_4$