It's harder to find one of the many genes involved in a polygenic trait vs the only gene involved in a discrete trait.
The role of the cruciate ligaments in maintaining the stability of the knee joint is delineated by experimental studies on 21 fresh adult knee specimens in addition to the analysis of symptoms in 111 cases of cruciate ligament injuries.
Answer:
Fracking and many other humans activities
Explanation:
Physical factors that affect population distribution include altitude and latitude, relief, climate, soils, vegetation, water and location of mineral and energy resources. It is important to note that most of the physical factors influence population distribution only indirectly through climatic conditions.
