Which plant's roots form a mycorrhizal association that is essential for its growth?

$A$ : Endosperm in $Cycas$ is haploid in nature.
$R$ : $Cycas$ roots show association with oxyphotobacteria.

With respect to the life cycle of $Pinus$,considering the formation of the female cone in the summer of year $0$,when does fertilization occur?

Coralloid roots are found in

The most advanced gymnosperms are included in the order ...... .

Canada balsam is an oleoresin obtained from