Nucleotides in DNA contain four different nitrogenous bases: Thymine, Cytosine, Adenine, or Guanine.
Pyrimidines: Cytosine and Thymine each have a single six-member ring. Purines: Guanine and Adenine each have a double ring made up of a five-atom ring attached by one side to a six-atom ring.
Answer:
Observations; control.
Explanation:
A hypothesis is considered to be tentative or an educated guess and can be defined as a testable explanation for an observation or a scientific problem. An example of a hypothesis is saying, Corona virus is caused by the introduction of the "5G" technology.
On the other hand, a control experiment can be defined as an experiment in which a condition assumed to be a probable cause of the effect is being compared to the same situation by the scientist without involving or using the suspected condition.
Hence, science rejects any hypothesis not supported by observations and the results of control experiments.
<em>This ultimately implies that, for any hypothesis to be acceptable in science, it must be supported by observations and the results of control experiments; this give rise to factual informations, theories and by extension solutions to problems.</em>
