Answer:
Explanation:
Key developments in blood transfusion techniques
• Animal experiments over the years 1900-1916 gradually enabled transfusion to become the routine technique it is today. The key developments were:
• George Crile (1907) perfected the technique of transfusion from artery to vein using dogs, and described its application in 32 patients.
• Hustin (1914) showed that addition of sodium citrate could prevent blood from clotting and that citrated blood could be safely transfused into dogs.
• Richard Lewisohn (1915) determined the maximum amount of citrate that could be transfused into dogs without toxicity and thus determined the optimum concentration that could be added to blood for the best anticoagulant effect.
• Weil (1915) showed that citrated blood could be stored for 2 days and still be effective when transfused into guinea-pigs and dogs which had lost blood.
• Rous and Turner (1916) used rabbits to demonstrate that, with certain additives and proper treatment, citrated blood could be stored for 14 days and still be successfully transfused.
Through these animal experiments, the prolonged storage of blood without clotting thus became possible, so enabling the establishment of blood banks, and blood transfusion as a routine procedure.
Answer:
Class Scyphozoa
Explanation:
In the Scyphozoa class, the predominant and sexual forms are beautiful medusas of varying colors, the true "medusas" often seen on our shores. The polyps are small and correspond to the asexual, short lasting phase. Since this class has the predominant species, the jellyfish, we can conclude that the class that the question is referring to is Scyphozoa.
The medusas are shaped like an umbrella and are different from the group of hydrozoans. They can reach from 2 to 40 cm in diameter. The giant of the group is a North Atlantic jellyfish that reaches 2 meters in diameter.
Answer:
Species of the genus Leishmania
Explanation:
The details of the research can be studied at : https://www.sciencemag.org/news/2009/09/mystery-desert
The only kingdom without cell walls is 'The fungi kingdom'
Answer: B. when sunlight is absorbed in chlorophyll
Explanation:
