The cells in embryo sac which act as haustoria are

Filiform apparatus is found in which part of angiosperms

Syngamy means

$A$ : Eight cells of octant stage in dicot embryogeny are made by $2$ vertical and one transverse divisions in
embryonal cell.
$R$ : These cells are arranged in epibasal and hypobasal tier.

Definations / Explanation :

$1.$ Nucellus

$2.$ Funicle