Answer
decomposers end the food chain but technically the food chain never stops
Answer:
To store genetic information to pass on to other living organisms.
DNA model given by Watson and Creek in the year of 1953 gave a very detailed study regarding the structure of B DNA which is valid till date and is essentially corroborating with Chargaff's data and Xray diffraction pattern.
<h3><u>Explanation:</u></h3>
The DNA is the most common nucleic acid found in the living organisms as a genetic material. As stated by Watson and Creek, this DNA contains a double helical structure with two sugar phosphate backbones and the nitrogen bases getting projected from it inwards. The backbones are formed of ribose sugar and phosphate and joined together with a phosphodiester bond. The ribose sugar is attached to phosphates at its 3' and 5' Carbon atoms. The nitrogen bases found in DNA are Adenine, Guanine, Thymine and Cytosine. The Adenine has two hydrogen bonds with thymine and guanine has 3 hydrogen bonds with cytosine.
Each full turn of a helix is 34A and each base pair is 3.4A apart. The distance between two strands of DNA is 20A.
Chargaff's rule regarding the equal amount of adenine and thymine as well as guanine and cytosine is matching with this structure. All the other rules also do match with this DNA structure.
<span>(3) parasite. Parasites are organisms that live on other organisms and cause harm to them.</span>
Black death, also known as the bubonic plague was one of the worst pandemics that ever happened, killing around 1/3 of Europe's population. It spread to Europe in the mid 1300's from China.
Black death victims were treated through magic, witchcraft, prayer and other methods. As for the two other options, they used medicine, but not antibiotics and radiation hadn't been discovered yet (it was discovered in the 1900's)