Answer:
4. The suspected causative agent must be isolated from the diseased host and grown in pure culture
Explanation:
Robert Koch (1843-1910) was one of the most important bacteriologists of all time. Famous for discovering the tuberculosis bacillus (precisely on March 24, such as today, in 1882), he also discovered the cholera bacillus and is considered the founder of bacteriology. He worked on the isolation of infectious agents and reinfections from pure cultures, experiences from which he established the "Koch Postulates".
These postulates have been taken as a reference that describes the etiology of all the causative agents of an infectious disease, although they were originally used to describe only the tuberculosis bacillus. They are the following:
1- The agent must be present in each case of the disease and absent in the healthy.
2- The agent should not appear in other diseases.
3- The agent must be isolated in a pure culture from the lesions of the disease.
4- The agent has to cause the disease in an animal that can be inoculated
Humans get D vitamin from sunlight. the plants perform photosynthesis and grow , we eat those fruits and vegetables grown in the plants. so indirectly we humans and other animals are benifitted from sun sunlight . flesh eating animals eat herbivores animala so they are also benifitted
Cohesive. This means that the water is attracted to other particles of itself, so they stick and bead up.
Isaac Newton published a comprehensive theory of gravity in 1687. Though others had thought about it before him, Newton was the first to create a theory that applied to all objects, large and small, using mathematics that was ahead of its time.
<span>The troposphere layer can have thunderstorms
or clear, sunny skies. The biosphere interacts most with this layer. </span>
The stratosphere is the second layer
from Earth's surface. Winds are strong and steady in this layer. <span>
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The mesosphere is heated by the ozone
layer beneath it. This layer is where most meteor showers occur.
The
thermosphere contains the ionosphere and exosphere. It contains layers of
single, unmixed gas.
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