Mutations in these genes result in abnormal or failed development of polarization in the Drosophila embryo. Nusslein-Volhard's experiments in 1979 identified and characterized all mutant alleles that affected the dorsal-ventral axis. Genes affecting dorsal-ventral polarization fall into two categories:
Biological warfare (BW)âalso known as germ warfare âis the use of biological toxins or infectious agents such as bacteria, viruses, and fungi with the intent to kill or incapacitate humans, animals or plants as an act of war.
Definition of Trench Warfare. Picture having to spend your life in a dark, cold, and dirty sewer system. You can't see much through the darkness, you're constantly wet because of the water that's flooded the tunnels, and you're in danger due to dirty conditions, lack of visibility, and disease-carrying rats.