Once during mitosis and twice during meiosis.
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A. light-independent reactions.
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.
The sensory receptors refer to the portions of the nervous system, which sense variations in the external or internal surroundings. The sensory input can be in various forms, comprising taste, pressure, light, sound, pH of blood, or levels of hormones, which are transformed into a signal and are transmitted to the brain or spinal cord.
In the sensory centers of the brain, the barrage of information is integrated and a response is produced. The response, that is, a motor output refers to a signal conducted towards organs via motor neurons, which then transforms the signal into some kind of action, like changes in heart rate, movement, discharge of hormones, and others.
