Ecosystems are characterized by the cycling of inorganic nutrients and the flow of

According to the question, ecosystems are characterized by the cycling of inorganic nutrients and the flow of Energy.

Ecosystem systems often maintain themselves through nutrients and energy cycling obtained from external sources.

The primary producers such as algae, plant and some bacteria at the first trophic level use solar energy to produce organic plant material using photosynthesis. Animal that rely on plant for its food (herbivores) makes up the second trophic level.  Predators that feed on herbivores make up the third trophic level: if there are presences of larger predators, they still represent higher predator level.  

Organism that feed on the higher trophic level is categorized based on the higher trophic level they feed on. Some of the organism that feed on the higher tropical level is grizzly bears and they eat berries and salmon. Decomposers such as fungi, molds, bacteria, worms and insects feed on waste and dead organisms and return nutrients back into the soil. Approximately 10% of the energy produced at a particular trophic level is transfer to another level.

Growth and reproduction, defecation and respiration are the various processes that reduce the transfer of energy from one trophic level to another. Another thing that also influences the transfer of energy is nutritional quality of material that is consumed.

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step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.