Linkage and crossing over of genes are alternatives of each other

Linkage and crossing over of genes are alternatives of each other. Justify with the help of an example.

Linkage is the tendency of certain loci or alleles (genes) to be inherited together while, crossing over is the segregation of genes, e.g. the genes on a chromosome either follow linkage path or cross over, to form the gametes during gametogenesis in human.