"In the early days of germ theory, contagious diseases
were thought to be caused by fungi or bacteria. In the 1890's, Dmitri
Ivanovski filtered extracts from diseased tobacco plants and discovered
that the disease could be transmitted to new plants through the
filtrate. He concluded that the disease was caused by particles smaller
than bacteria; the tobacco mosaic virus", is partially correct. Dmitri
Ivanovski discovered that filtered extracts from diseased tobacco plants
could be transmitted to new plants through the filtrate. However, it
was Dutch microbiologist Martinus Beijerinck who, while replicating
Ivanovsky's experiments, proved that the filtrate contained a new
infectious agent. Beijerinck named this agent a virus.
I believe it is Wegener's theory did not explain how the continents could move.
Answer:
The history of GIS all started in 1854. Cholera hit the city of London, England. British physician John Snow began mapping outbreak locations, roads, property boundaries, and water lines.
John Snow’s Cholera map was a major event connecting geography and public health safety. Not only was this the beginning of spatial analysis, but it also marked the start of a whole field of study: Epidemiology – the study of the spread of disease.
To this date, John Snow is known as the father of epidemiology. The work of John Snow demonstrated that GIS is a problem-solving tool. He put geographic layers on a paper map and made a life-saving discovery.
Explanation:
Secretion of human chorionic gonadotropin [HCG] only occur during pregnancy in the placenta. The concentration of this hormone increase rapidly during the first three months of pregnancy; the amount in the blood stream doubles every two to three days as the development of the placenta and embryo progress. The hormone reaches its maximum concentration peak around the sixth week of pregnancy and after this, its concentration decline.
A is the answer I would choose :) amos 12kvng
