Answer:
- Glacial deposits and scratches in the bedrock from an ice sheet match in distant regions
- Fossils of marsupials were originally the same across South America and Australia
- Cratons match across the edges of continents
Explanation:
South America, Africa, Antarctica, and Australia were all once part of one super-continent. This super-continent has been named Gondwanaland. As the geological processes got more intensive though and Gondwanaland separated into smaller land masses, continents, which we now know as the continents on the Southern Hemisphere. There are numerous clues that confirm that these continents were once connected. Some of the clues are the matching cratons on the edges of the continents, the glacial deposits and scratches in the bedrock are also matching, lot of fossilized flora and fauna from the same species have been found in several of these continents, the marsupials in South America and Australia etc.
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.
Recombinant DNA is a type of artificial DNA which have genes that are taken from different organisms. During this process, a gene is take from one organism and putting the gene into another organism. Basically, the technology follows cut and paste scheme to form the new brand of DNA.
So to conclude this the technology cuts part of the DNA out to create a new DNA so you are cutting and pasting new DNA which is incredible.
Hope this helped.
Answer:Primary succession occurs on land that is new and has never had a flora and fauna example: glacier retreats, lava flows. Secondary succession occurs on land that has been cleared example: by fire, of flora and fauna, but which still has viable seeds and spores in the soil.
