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.
<span>Within a more biodiverse ecosystem, there is a higher chance that species will be able to adapt to change. For example, even with the eradication or migration of any one particular food group, consumers higher up in the food chain will remain able to survive due to alternative sources of energy.</span>
Answer:
Secondary level of protein structure
Explanation:
The proteins are formed of the monomer units called amino acids which bond with each other via peptide bond and form a linear peptide structure called the primary level structure of the protein.
The proteins to perform several functions in a cell undergoes structural conformation and attain the helical form called alpha helix due to the involvement of alpha carbon in bond formation and a pleated sheet called beta-pleated sheet due to the involvement of beta carbon. These structures are known as a secondary level of protein structure.
Thus, a Secondary level of protein structure is the correct answer.
Answer:
I did this and i got A. I got it correct so you should too.
