Which of these is not a contrivance for cross pollination?

Assertion $\left(\mathrm{A}\right)$: Cleistogamous flowers produce assured seed set in the absence of pollinators

Reason $\left(\mathrm{R}\right)$: Cleistogamy is invariably an Autogamy

Commelina produces flowers which are open and are similar to flowers of other species with exposed anthers and stigma are called ______.

A typical angiospermic embryo sac, at maturity, contains ________ nuclei and _______ cells.