Why cant patterns of in heritance in humans be easily studied as in peas or fruit flies?

Patterns of inheritance in humans are more complex than in peas or fruit flies due to factors such as multiple alleles, incomplete dominance, co-dominance, polygenic traits, and environmental influences. In addition, ethical considerations limit the ability to conduct controlled breeding experiments in humans as can be done with plants and animals in a laboratory setting. This complexity makes it challenging to isolate and study specific genetic traits in human populations.