challenge: What were some of the fields of study that Erna Walter was known for?
  
  A. Botany, Ecology, Botanical collecting, and Bryology
  B. Botany, Ecology, Entomology, and Geology
  C. Zoology, Microbiology, Botany, and Ecology
  D. Genetics, Paleontology, Botany, and Ecology
  Answer: 