Dr. marshall demonstrated that gastric ulcers are caused by a bacterium by using Koch’s postulates.
Koch’s postulates are four standards created to confirm a causative relationship between a microorganism and a disease. Koch’s postulates were formulated in 1884 by Robert Koch and Friedrich Loeffler. Koch’s postulates include;
- the microorganism must be found in every cases of the disease.
- the microorganism must be isolated from the diseased host and grown in pure culture
.
- the cultured microorganism must cause the disease when introduced into a healthy laboratory animal
.
- the microorganism must be re-isolated from the new host and identified to be the same as the original causative agent
.
The correct option is: GRATINIC ROCK IN THE OCEAN FLOOR.
Sea floor spreading refers to the process by which molten materials add new oceanic crust to the ocean floor. This process occurs slowly across the earth's middle ocean ridges. Harry Hess formulated an hypothesis to explain the phenomenon of sea floor spreading and all the above options support his hypothesis with the exception of option C.
Answer:
1. False
2. True
3. True
4. False
Explanation:
In mammals, the contraction of the heart muscle is caused by pacemaker cells localized within the sinoatrial (SA) node. These cells rhythmically generate slow electrically-induced action potentials due to their slow rate of depolarization. The pacemaker cells generate the action potentials that propagate through the heart and trigger the contraction of myocyte cells (i.e., myocytes simply conduct the action potential waves). The slow depolarization of pacemaker cells occurs during diastole, i.e., during the period of relaxation of the heart muscle.
Kidney stones are stones caused by the precipitation of minerals, such as calcium, and other substances from the urine or kidney filtrate.
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What are Kidney stones?</h3>
These are hard deposits of minerals such as calcium etc which stick together in the urine of affected individuals.
This thereby causes pain when urine is being expelled from the body as a result of the large size.
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