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.
All they need for their living is carbondioxide in air ,water and some nutrients .so basically their roots are responsible for collection of water which contains life giving nutrients .but we take food as a solid substance which hasto be converted into energy
Answer: I think it's through tropical level
Explanation:
Answer:
Taxonomy allows a better understanding of relationships among species.
Explanation:
Answer:
what ecosystem are yall talking about
