Answer:
Nitrogenous bases contain the genetic information, their amount is variable among different species, and the arrangement of these bases is also variable among different species
Explanation:
Both Watson-Crick and Pauling's DNA models considered that DNA nitrogenous bases (i.e., Adenine, Cytosine, Thymine and Guanine) contain the genetic information that determines the characteristics of living organisms. Moreover, both DNA models also considered that nitrogenous base composition varies between species, as well as the arrangement of these bases in the DNA chain also varies between species. Based on these features, Linus Pauling considered that a model where nitrogenous bases would be arranged on the outside of the DNA molecule would be easier for the DNA molecule to be replicated, transcribed, or repaired. Although incorrect, Pauling's DNA triple helix model was fundamental to develop the helical (double-stranded) structure of DNA, which was finally discovered by Watson and Crick in 1953.
Answer:
excretory system
Explanation:
The excretory system is the system of an organism's body that performs the function of excretion, the bodily process of discharging wastes. ... There are several parts of the body that are involved in this process, such as sweat glands, the liver, the lungs and the kidney system. Every human has two kidneys.
Answer:
replacing defective blood-making cells
Explanation:
The first vertebrates appeared in the Paleozoic Era, specifically the Cambrian period. The vertebrates were <span>jawless fish with backbones made out of cartilages. It was thought that the first fishes evolved during this period. The correct answer to this question is letter "A. Cambrian". I hope this helps.</span>
This is the First Law of Thermodynamics. It's also called the Law of Conservation of Energy.
