What structure forms during angiosperm fertilization but does not form during fertilization among other types of plants?

A triploid  cell   is  the    structure   form   during  angoisperm  fertilization. The   cell  are created   in  the  process  known   as  double   fertilization  into   the  endosperm   which  is   mostly   are    polyploid. These  are  typicallly  triploids   that  is  they   contain  three  sets  of  chromosomes   but  they   varies  widely  from   diploid  (2n)  to   15N.

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What have scientists learned about plant behavior by studying the dodder plant