<h3><u>Answer and Explanation</u>;</h3>
- Purines: Heterocyclic rings are synthesized one atom at a time, first atom attached to ribose phosphate (source is PRPP) and then all the other atoms are added .
- Pyrimidines: Common intermediate, orotate, synthesized first, then orotate is attached to ribose phosphate (source is PRPP or 5-Phosphoribosyl-1-pyrophosphate).
Klinglers iron agar medium is used to find the enterobacteria which can ferment glucose , lactose and hydrogen Sulphide . They are H₂S producing bacteria .
This media have phenol red as an indicator. When the glucose is fermented to acid , the production of acid turn the indicator from red to yellow, but it is then reoxidised and turns red again . When lactose is fermented it produce large amount of acid , and turn indicator yellow . Hence the slant will become yellow.And combination of ferrous sulphate and sodium thiosulphate helps in detection of H₂S which produce black color at the butt .
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Answer: Timber industry, paper industry, furniture industry.
ANSWER: B: ONE OF THE SPIRAL ARMS OF THE MILKY WAY
Explanation: There are many arms to every galaxy, in our case, the Milky Way. To each spiral arm is one solar system, which is also why it so difficult to explore space.