In the sitcom the big bang theory, several main characters, acclaimed and successful scientists, try unsuccessfully to approach attractive women for dates. in the perceptual process, which stage is probably causing the most problems, given that the women see "geeky", unattractive, socially awkward men?

 in the perceptual process, the stage that is probably causing the most problems would be: Organiaztion stage

In The organization stage of the perceptual process, females will mentally arrange stimuli into meaningful and comprehensible patterns.
During this stage, women will categorize men based on their Social hierarchy, appearance and other stereotypes to determine whether the men is a suitable mate.

The changes to agriculture in the united states since 1900 is that increased mechanization has increased food production, thereby increasing the need for labor. there has been an increased need for higher speeds of food production due the fact that the population in the united states continues to rise.