Membrane proteins may extend partway into the plasma membrane and cross the membrane entirely or be loosely attached to its inside or outside face
Prophase I would be correct...
<span>Organisms used to be classified in the earliest times according to their size. As science progressed, they started getting organized by their physical traits and now they're organized by traits found in their species that are not found in others based on the theory of evolution. They are classified according to how they developed from a starting organism.</span>
Answer:
The nucleic acid is a macromolecule present in living systems in the form of either DNA or RNA, whose molecule consists of many nucleotides which are linked with each other to form long chains. The presence of DNA or RNA in an individual promotes continuity of life. The variability and complexity of nucleic acid are dependent on its constituent molecules as, sugar, a phosphate group, and a nitrogenous base. However, two monocyclic nitrogenous bases were classified purines (adenine:A, guanine:G) and pyrimidines (thymine:T, cytosine:C, and uracil:U).
In addition, RNA is a single-stranded structure which differs from DNA in two aspects, the sugar content of RNA is ribose, and pyrimidine base uracil replaces the thymine base of DNA. A ratio between two strands of DNA can be calculated by using Chargrff's rule which states that "DNA from any cell of all organisms possess a 1:1 ratio (base Pair Rule) of pyrimidine and purine bases'.
The purine to pyrimidine ratio in RNA with different bases is given below in the following table:
Presence of single strand in RNA does not follow chargaff's rule and alters the purine: pyrimidine ratio. The above ratio of each base in the given information is not equal, due to which the ratio of purines to pyrimidines is different. The ratio of DNA and RNA is not equal because DNA has its complementary DNA strand. However, bases in RNA might vary due to its single-strandedness property, but its ratio is dependent on the species.
Therefore, it can be concluded that the ratio of purines to pyrimidines is dependent on the species due to its genetic makeup. Hence, option (c) is correct.
<span>All of the following patterns were witnessed by Darwin except that species vary within very short spans of time. Charles Darwin put forth a coherent theory of evolution and amassed a great body of evidence in support of this theory. By the 19th Century, a number of natural historians were beginning to think of evolutionary change as an explanation for patterns observed in nature.</span>