Give scientific reasons: Outbreeding devices increase fertility.

(N/A) Outbreeding devices are mechanisms developed by flowering plants to discourage self-pollination and encourage cross-pollination.
$1$. Prevention of Inbreeding Depression: Continuous self-pollination leads to inbreeding depression,which reduces the genetic diversity and vigor of the offspring over generations.
$2$. Genetic Variation: Cross-pollination introduces new combinations of genes,leading to increased genetic variation,which enhances the adaptability and survival of the species in changing environments.
$3$. Increased Vigor: Offspring produced through cross-pollination often exhibit 'hybrid vigor' or heterosis,resulting in healthier,more robust,and more fertile plants compared to those produced by self-pollination.
$4$. Evolutionary Advantage: By promoting cross-pollination,outbreeding devices ensure that the population remains genetically healthy and capable of evolving,thereby maintaining high fertility levels within the species.