Answer:
The correct answer is b. He determined that DNA contains four nitrogenous bases.
Explanation:
Levene was an American biochemist who studied the structure of DNA in the early 1900s and in 1920 he found that DNA consists of four nitrogenous bases that are Adenine, Guanine, Thymine, Cytosine.
He also found deoxyribose sugar and phosphate group and said that nucleotide is the basic unit of DNA which contains a ribose sugar with attached nitrogenous base and phosphate group.
He also concludes that an equal amount of adenine, guanine, thymine, and cytosine makes the DNA which is now known as tetranucleotide hypothesis. So the correct answer is b. He determined that DNA contains four nitrogenous bases.
Arabian plate and Eurasian plate is the correct answer.
Answer: Option B
Explanation:
In a typical energy pyramid the amount of energy that is being transferred is only 10% rest of the energy is lost in the form of heat.
The energy from the sun is converted in the form of chemical energy which is stored in the producers.
10 per cent of this energy is transferred to the next trophic level and rest of the energy is lost in the form of heat. This goes on, there is only a transfer of 10 % energy from the successive levels.
So, if the producers have 200 Kcal/m2/year energy the the primary consumers will have 10% of this energy which is equivalent to 20 Kcal/m2/year and then the secondary consumers will have 10 % of 20 Kcal/m2/year which is equivalent to 2 Kcal/m2/year.
C
hope this helps u to understand.
