If the number of chromosome present in the egg of a gymnosperm plant is 10, then the number of chromosomes present in the endosperm of the same plant is

In gymnosperms, the female gametophyte itself is endosperm as it nourishes the developing embryo. Hence it is haploid. The egg cell present in the archegonium of gymnosperm's female gametophyte is also haploid. Hence the chromosome number 10 remains the same.