A closed system is a system that makes no physical or chemical exchanges with its environment. Of these systems provided as choices (tree, human, clock, car), only a clock does not make exchanges with the environment, except for energy.
Therefore, of that list, only a clock would be a closed system.
Hope that helped! =)
Can you give more information?
Answer:
Ribosomal RNA (rRNA) associates with a set of proteins to form ribosomes. These complex structures, which physically move along an mRNA molecule, catalyze the assembly of amino acids into protein chains. They also bind tRNAs and various accessory molecules necessary for protein synthesis.
Explanation:
Ribosomal RNA (rRNA) associates with a set of proteins to form ribosomes. These complex structures, which physically move along an mRNA molecule, catalyze the assembly of amino acids into protein chains. They also bind tRNAs and various accessory molecules necessary for protein synthesis.
This statement means that evolution has happened by getting the genes of the right trait expressed at the right time to help adaptability.
Explanation:
Evolution is a result of natural selection which emphasize on the survival of the fittest. But the occurrence of this trait has been possible with genetic variation. It means that if the genes for the particular feature is not present in the genome how would it occur and adapt to the environment. Thus, evolution promotes the most available option for the adaptation and hence for natural selection.
We can conclude that all features are not adaptable some are the results of genetic drift or mutations.
In case of cheetah, the faster running genes would have been there they got expressed over the period of time for better adaptability.
Answer:
Kristin's answer is the best.
Explanation:
It is the only correct answer.