Dr. Semmelweis, a physician from Austria, wanted to locate the cause of childbed
fever in his maternity wards. He suggested that the doctors in the hospital were
transferring a disease-causing substance to the pregnant mothers because they were
not washing their hands. His suggestion was a:
A. observation
B. hypothesis
C. theory
D. controlled experiment

Dr. Semmelweis, a physician from Austria, wanted to locate the cause of child-bed  fever in his maternity wards. He suggested that the doctors in the hospital were  transferring a disease-causing substance to the pregnant mothers because they were  not washing their hands. His suggestion was a:

observation

Explanation:

Dr Semmelweis only observed what could have caused the child-bed fever since there is no migration of people from elsewhere it shows that it is only within the terrain are causing the transmission within themselves.

when the displaced particles are perpendicular to the direction the wave travels, is called a transverse wave, whereas in longitudinal wave the displace practices are parallel to the direction of the wave.

in the given image:

first image shows - longitudinal wave

second image shows - transverse wave

third image shows - longitudinal wave

fourth image shows - longitudinal wave