Which of the following types of embryo sac is commonly found in angiosperms?

$A$ $Drusa$ type of embryo sac is:

The megasporangium is equivalent to which of the following?

The tissue that attaches the ovule to the inner side of the ovary is called .......

$A$ mature embryo sac at the final stage of development contains: (in $cells$)

Choose the correct sentence$(s)$.
$(I)$ Nucleus of the functional megaspore divides meiotically to form two nuclei.
$(II)$ After the $8$-nucleate stage,cell walls are laid down leading to the organization of a typical female gametophyte.
$(III)$ The egg apparatus consists of two synergids and one egg cell.
$(IV)$ Three cells at the chalaza end are called antipodal cells.