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.
Answer:
Sympatric speciation.
Explanation:
Sympatric speciation is a type of speciation that occurs when 2 types of groups of the common species live in the common geographic location, but they grow differently until they can no longer interbreed and are known as different species.
This speciation can occur in different types of species such as bacteria, the apple maggot fly, and cichlid fish, but it is difficult to tell when this speciation is happening or has occurred in nature. There are four types of speciation occurs:
1) Symmetric
2) Allopathic
3) Parapatric
4) Peripatric.
YES your correct answer will be the letter B
An experiment is a process where the a scientist tests and draws their evidence and data from. Hence, this process is where the hypothesis be supported or negated.
Variables are traits, factors, or characteristics that either manipulated or measured being the subject to become the data.
The independent variable is B.
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