Resin and turpentine are obtained from $..........$.

Which of the following gymnospermic coralloid roots are associated with $N_{2}$-fixing cyanobacteria?

$A$: Microspores and megaspores are produced in the same lax in gymnosperms.
$R$: Lax represents a compact strobilus which bears microsporophyll and megasporophyll.

Male and female cones both are present in the same plant in $:-$

In $Pinus$,only the lower part of the oospore is concerned with the development of the embryo. Such development is known as:

Nitrogen fixation occurs in coralloid roots of $Cycas$ with the help of: