Answer:
Prophase 1
Explanation:
Prophase I :It can be divided into five stages:
1)Leplotene: In this stage, chromosome becomes visible and shorten as a single structure.
2)Zygotene: Homologous / sister chromosome pair up. This process is known as synapse. Synapse is the process of attachment of homologous /sister chromosome. One pair comes from the male parent while the other comes from the female parent.
3)Pachytene: Bivalents shorten.
4)Diplotene:Point of attachment of non-sister chromatids. The two chromosomes are seen to be joined at several points along their length. These points are known as Chiasmata.(Chiasmata, a cross). The paternal gene A, B, C may swap for the maternal gene a, b, c for instance, leading to a new gene combination in the resulting chromatids. This is referred to as *CROSSING OVER*.
5)Diakenesis: Homologous centromere move apart.
So, crossing over occurs in *Prophase 1.
Answer:
Nitrogen and Phosphorus
Explanation:
When the function of a whole ecosystem is limited because of a nutrient , which is present in limited amount, it is called as a limiting nutrient. The organisms uptake water and carbon directly from the environment as it is abundant in nature. The nutrients like nitrogen and phosphorous are present in limited amount and moreover they are not present in the form that can be directly taken up by the organism.
Thus, Nitrogen and Phosphorous are limiting nutrients.
Answer:
The hershey chase experiment on bacteriophages showed the genetic information is carried in <u>DNA.</u>
Explanation:
In 1952 Alfred Hershey and Martha Chase provided evidence that DNA is the genetic material. These scientists carried out an experimental work with the T2 virus, a bacteriophage that infects the Escherichia coli bacteria, which reproduces by attaching itself to the outer wall of the bacteria, injecting its DNA into it where it replicates and directs, the synthesis of phage proteins. Phage DNA is encapsulated within proteins and produces phages, which lyse or break the cell and releasing phage from the progeny. They used radioactive forms (isotopes) of phosphorus and sulfur. A radioactive isotope can be used as a marker to identify the location of a specific molecule, because any molecule that contains the isotope is radioactive and therefore easy to detect. The DNA contains phosphorus, but doesn't contain sulfur, therefore phosphorus-32 was used to mark the DNA, instead the protein has sulfur, but not phosphorus, so sulfur-35 was used. Hershey and Chase found that sulfur-35 is outside the cell while phosphorus-32 was inside, indicating that DNA was the physical support of the inheritance. This work allowed the scientists to conclude that it's the DNA and not the protein that enters the bacteria during phage reproduction and that only the DNA is transmitted to the phage of the progeny.
Answer:
C: piedmont
Explanation:
Catawbas tribe lived in the Carolina Piedmont
